Doping (semiconductor)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Doping_(semiconductor)

 

In semiconductor production, doping is the intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties. The doped material is referred to as an extrinsic semiconductor. A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as a degenerate semiconductor.

In the context of phosphors and scintillators, doping is better known as activation. Doping is also used to control the color in some pigments.

History

The effects of semiconductor doping were long known empirically in such devices as crystal radio detectors and selenium rectifiers. For instance, in 1885 Shelford Bidwell, and in 1930 the German scientist Bernhard Gudden, each independently reported that the properties of semiconductors were due to the impurities contained within them. The doping process was formally first developed by John Robert Woodyard working at Sperry Gyroscope Company during World War II, with a US Patent issued in 1950. The demands of his work on radar denied Woodyard the opportunity to pursue research on semiconductor doping. 

Similar work was performed at Bell Labs by Gordon K. Teal and Morgan Sparks, with a US Patent issued in 1953.

Woodyard's prior patent proved to be the grounds of extensive litigation by Sperry Rand .

Carrier concentration

The concentration of the dopant used affects many electrical properties. Most important is the material's charge carrier concentration. In an intrinsic semiconductor under thermal equilibrium, the concentrations of electrons and holes are equivalent. That is,

${\displaystyle n=p=n_{i}.\ }$

In a non-intrinsic semiconductor under thermal equilibrium, the relation becomes (for low doping):

${\displaystyle n_{0}\cdot p_{0}=n_{i}^{2}\ }$

where n₀ is the concentration of conducting electrons, p₀ is the conducting hole concentration, and n_i is the material's intrinsic carrier concentration. The intrinsic carrier concentration varies between materials and is dependent on temperature. Silicon's n_i, for example, is roughly 1.08×10¹⁰ cm⁻³ at 300 kelvins, about room temperature.

In general, increased doping leads to increased conductivity due to the higher concentration of carriers. Degenerate (very highly doped) semiconductors have conductivity levels comparable to metals and are often used in integrated circuits as a replacement for metal. Often superscript plus and minus symbols are used to denote relative doping concentration in semiconductors. For example, n⁺ denotes an n-type semiconductor with a high, often degenerate, doping concentration. Similarly, p⁻ would indicate a very lightly doped p-type material. Even degenerate levels of doping imply low concentrations of impurities with respect to the base semiconductor. In intrinsic crystalline silicon, there are approximately 5×10²² atoms/cm³. Doping concentration for silicon semiconductors may range anywhere from 10¹³ cm⁻³ to 10¹⁸ cm⁻³. Doping concentration above about 10¹⁸ cm⁻³ is considered degenerate at room temperature. Degenerately doped silicon contains a proportion of impurity to silicon on the order of parts per thousand. This proportion may be reduced to parts per billion in very lightly doped silicon. Typical concentration values fall somewhere in this range and are tailored to produce the desired properties in the device that the semiconductor is intended for. 

Effect on band structure

Band diagram of PN junction operation in forward bias mode showing reducing depletion width. Both p and n junctions are doped at a 1×10¹⁵/cm³ doping level, leading to built-in potential of ~0.59 V. Reducing depletion width can be inferred from the shrinking charge profile, as fewer dopants are exposed with increasing forward bias.

 

Doping a semiconductor in a good crystal introduces allowed energy states within the band gap, but very close to the energy band that corresponds to the dopant type. In other words, electron donor impurities create states near the conduction band while electron acceptor impurities create states near the valence band. The gap between these energy states and the nearest energy band is usually referred to as dopant-site bonding energy or E_B and is relatively small. For example, the E_B for boron in silicon bulk is 0.045 eV, compared with silicon's band gap of about 1.12 eV. Because E_B is so small, room temperature is hot enough to thermally ionize practically all of the dopant atoms and create free charge carriers in the conduction or valence bands.

Dopants also have the important effect of shifting the energy bands relative to the Fermi level. The energy band that corresponds with the dopant with the greatest concentration ends up closer to the Fermi level. Since the Fermi level must remain constant in a system in thermodynamic equilibrium, stacking layers of materials with different properties leads to many useful electrical properties induced by band bending, if the interfaces can be made cleanly enough. For example, the p-n junction's properties are due to the band bending that happens as a result of the necessity to line up the bands in contacting regions of p-type and n-type material. This effect is shown in a band diagram. The band diagram typically indicates the variation in the valence band and conduction band edges versus some spatial dimension, often denoted x. The Fermi level is also usually indicated in the diagram. Sometimes the intrinsic Fermi level, E_i, which is the Fermi level in the absence of doping, is shown. These diagrams are useful in explaining the operation of many kinds of semiconductor devices.

Relationship to carrier concentration (low doping)

For low levels of doping, the relevant energy states are populated sparsely by electrons (conduction band) or holes (valence band). It is possible to write simple expressions for the electron and hole carrier concentrations, by ignoring Pauli exclusion (via Maxwell–Boltzmann statistics):

${\displaystyle n_{e}=N_{\rm {C}}(T)\exp((E_{\rm {F}}-E_{\rm {C}})/kT),\quad n_{h}=N_{\rm {V}}(T)\exp((E_{\rm {V}}-E_{\rm {F}})/kT),}$

where E_F is the Fermi level, E_C is the minimum energy of the conduction band, and E_V is the maximum energy of the valence band. These are related to the value of the intrinsic concentration via^[7]

${\displaystyle n_{i}^{2}=n_{h}n_{e}=N_{\rm {V}}(T)N_{\rm {C}}(T)\exp((E_{\rm {V}}-E_{\rm {C}})/kT),}$

an expression which is independent of the doping level, since E_C – E_V (the band gap) does not change with doping. 

The concentration factors N_C(T) and N_V(T) are given by

${\displaystyle N_{\rm {C}}(T)=2(2\pi m_{e}^{*}kT/h^{2})^{3/2}\quad N_{\rm {V}}(T)=2(2\pi m_{h}^{*}kT/h^{2})^{3/2}.}$

where m_e^* and m_h^* are the density of states effective masses of electrons and holes, respectively, quantities that are roughly constant over temperature.

Techniques of doping and synthesis

The synthesis of n-type semiconductors may involve the use of vapor-phase epitaxy. In vapor-phase epitaxy, a gas containing the negative dopant is passed over the substrate wafer. In the case of n-type GaAs doping, hydrogen sulfide is passed over the gallium arsenide, and sulfur is incorporated into the structure. This process is characterized by a constant concentration of sulfur on the surface. In the case of semiconductors in general, only a very thin layer of the wafer needs to be doped in order to obtain the desired electronic properties. The reaction conditions typically range from 600 to 800 °C for the n-doping with group VI elements, and the time is typically 6–12 hours depending on the temperature. 

Process

Some dopants are added as the (usually silicon) boule is grown, giving each wafer an almost uniform initial doping. To define circuit elements, selected areas — typically controlled by photolithography — are further doped by such processes as diffusion and ion implantation, the latter method being more popular in large production runs because of increased controllability.

Small numbers of dopant atoms can change the ability of a semiconductor to conduct electricity. When on the order of one dopant atom is added per 100 million atoms, the doping is said to be low or light. When many more dopant atoms are added, on the order of one per ten thousand atoms, the doping is referred to as high or heavy. This is often shown as n+ for n-type doping or p+ for p-type doping.

Dopant elements

Group IV semiconductors

(Note: When discussing periodic table groups, semiconductor physicists always use an older notation, not the current IUPAC group notation. For example, the carbon group is called "Group IV", not "Group 14".) 

For the Group IV semiconductors such as diamond, silicon, germanium, silicon carbide, and silicon germanium, the most common dopants are acceptors from Group III or donors from Group V elements. Boron, arsenic, phosphorus, and occasionally gallium are used to dope silicon. Boron is the p-type dopant of choice for silicon integrated circuit production because it diffuses at a rate that makes junction depths easily controllable. Phosphorus is typically used for bulk-doping of silicon wafers, while arsenic is used to diffuse junctions, because it diffuses more slowly than phosphorus and is thus more controllable.

By doping pure silicon with Group V elements such as phosphorus, extra valence electrons are added that become unbonded from individual atoms and allow the compound to be an electrically conductive n-type semiconductor. Doping with Group III elements, which are missing the fourth valence electron, creates "broken bonds" (holes) in the silicon lattice that are free to move. The result is an electrically conductive p-type semiconductor. In this context, a Group V element is said to behave as an electron donor, and a group III element as an acceptor. This is a key concept in the physics of a diode. 

A very heavily doped semiconductor behaves more like a good conductor (metal) and thus exhibits more linear positive thermal coefficient. Such effect is used for instance in sensistors. Lower dosage of doping is used in other types (NTC or PTC) thermistors. 

Silicon dopants

• Acceptors, p-type
  • Boron is a p-type dopant. Its diffusion rate allows easy control of junction depths. Common in CMOS technology. Can be added by diffusion of diborane gas. The only acceptor with sufficient solubility for efficient emitters in transistors and other applications requiring extremely high dopant concentrations. Boron diffuses about as fast as phosphorus.
  • Aluminium, used for deep p-diffusions. Not popular in VLSI and ULSI. Also a common unintentional impurity.
  • Gallium is a dopant used for long-wavelength infrared photoconduction silicon detectors in the 8–14 µm atmospheric window. Gallium-doped silicon is also promising for solar cells, due to its long minority carrier lifetime with no lifetime degradation; as such it is gaining importance as a replacement of boron doped substrates for solar cell applications.
  • Indium is a dopant used for long-wavelength infrared photoconduction silicon detectors in the 3–5 µm atmospheric window.
• Donors, n-type
  • Phosphorus is a n-type dopant. It diffuses fast, so is usually used for bulk doping, or for well formation. Used in solar cells. Can be added by diffusion of phosphine gas. Bulk doping can be achieved by nuclear transmutation, by irradiation of pure silicon with neutrons in a nuclear reactor. Phosphorus also traps gold atoms, which otherwise quickly diffuse through silicon and act as recombination centers.
  • Arsenic is a n-type dopant. Its slower diffusion allows using it for diffused junctions. Used for buried layers. Has similar atomic radius to silicon, high concentrations can be achieved. Its diffusivity is about a tenth of phosphorus or boron, so it is used where the dopant should stay in place during subsequent thermal processing. Useful for shallow diffusions where well-controlled abrupt boundary is desired. Preferred dopant in VLSI circuits. Preferred dopant in low resistivity ranges.
  • Antimony is a n-type dopant. It has a small diffusion coefficient. Used for buried layers. Has diffusivity similar to arsenic, is used as its alternative. Its diffusion is virtually purely substitutional, with no interstitials, so it is free of anomalous effects. For this superior property, it is sometimes used in VLSI instead of arsenic. Heavy doping with antimony is important for power devices. Heavily antimony-doped silicon has lower concentration of oxygen impurities; minimal autodoping effects make it suitable for epitaxial substrates.
  • Bismuth is a promising dopant for long-wavelength infrared photoconduction silicon detectors, a viable n-type alternative to the p-type gallium-doped material.
  • Lithium is used for doping silicon for radiation hardened solar cells. The lithium presence anneals defects in the lattice produced by protons and neutrons. Lithium can be introduced to boron-doped p+ silicon, in amounts low enough to maintain the p character of the material, or in large enough amount to counterdope it to low-resistivity n type.
• Other
  • Germanium can be used for band gap engineering. Germanium layer also inhibits diffusion of boron during the annealing steps, allowing ultrashallow p-MOSFET junctions. Germanium bulk doping suppresses large void defects, increases internal gettering, and improves wafer mechanical strength.
  • Silicon, germanium and xenon can be used as ion beams for pre-amorphization of silicon wafer surfaces. Formation of an amorphous layer beneath the surface allows forming ultrashallow junctions for p-MOSFETs.
  • Nitrogen is important for growing defect-free silicon crystal. Improves mechanical strength of the lattice, increases bulk microdefect generation, suppresses vacancy agglomeration.
  • Gold and platinum are used for minority carrier lifetime control. They are used in some infrared detection applications. Gold introduces a donor level 0.35 eV above the valence band and an acceptor level 0.54 eV below the conduction band. Platinum introduces a donor level also at 0.35 eV above the valence band, but its acceptor level is only 0.26 eV below conduction band; as the acceptor level in n-type silicon is shallower, the space charge generation rate is lower and therefore the leakage current is also lower than for gold doping. At high injection levels platinum performs better for lifetime reduction. Reverse recovery of bipolar devices is more dependent on the low-level lifetime, and its reduction is better performed by gold. Gold provides a good tradeoff between forward voltage drop and reverse recovery time for fast switching bipolar devices, where charge stored in base and collector regions must be minimized. Conversely, in many power transistors a long minority carrier lifetime is required to achieve good gain, and the gold/platinum impurities must be kept low.

Other semiconductors

• Gallium arsenide
  • n-type: tellurium, sulphur (substituting As), tin, silicon, germanium (substituting Ga)
  • p-type: beryllium, zinc, chromium (substituting Ga), silicon, germanium (substituting As)
• Gallium phosphide
  • n-type: tellurium, selenium, sulphur (substituting phosphorus)
  • p-type: zinc, magnesium (substituting Ga), tin (substituting P)
• Gallium nitride, Indium gallium nitride, Aluminium gallium nitride
  • n-type: silicon (substituting Ga), germanium (substituting Ga, better lattice match), carbon (substituting Ga, naturally embedding into MOVPE-grown layers in low concentration)
  • p-type: magnesium (substituting Ga) - challenging due to relatively high ionisation energy above the valence band edge, strong diffusion of interstitial Mg, hydrogen complexes passivating of Mg acceptors and by Mg self-compensation at higher concentrations)
• Cadmium telluride
  • n-type: indium, aluminium (substituting Cd), chlorine (substituting Te)
  • p-type: phosphorus (substituting Te), lithium, sodium (substituting Cd)
• Cadmium sulfide
  • n-type: gallium (substituting Cd), iodine, fluorine (substituting S)
  • p-type: lithium, sodium (substituting Cd)

Compensation

In most cases many types of impurities will be present in the resultant doped semiconductor. If an equal number of donors and acceptors are present in the semiconductor, the extra core electrons provided by the former will be used to satisfy the broken bonds due to the latter, so that doping produces no free carriers of either type. This phenomenon is known as compensation, and occurs at the p-n junction in the vast majority of semiconductor devices. Partial compensation, where donors outnumber acceptors or vice versa, allows device makers to repeatedly reverse (invert) the type of a given portion of the material by applying successively higher doses of dopants, so-called counterdoping. Most modern semiconductors are made by successive selective counterdoping steps to create the necessary P and N type areas.

Although compensation can be used to increase or decrease the number of donors or acceptors, the electron and hole mobility is always decreased by compensation because mobility is affected by the sum of the donor and acceptor ions.

Doping in conductive polymers

Conductive polymers can be doped by adding chemical reactants to oxidize, or sometimes reduce, the system so that electrons are pushed into the conducting orbitals within the already potentially conducting system. There are two primary methods of doping a conductive polymer, both of which use an oxidation-reduction (i.e., redox) process.

1. Chemical doping involves exposing a polymer such as melanin, typically a thin film, to an oxidant such as iodine or bromine. Alternatively, the polymer can be exposed to a reductant; this method is far less common, and typically involves alkali metals.
2. Electrochemical doping involves suspending a polymer-coated, working electrode in an electrolyte solution in which the polymer is insoluble along with separate counter and reference electrodes. An electric potential difference is created between the electrodes that causes a charge and the appropriate counter ion from the electrolyte to enter the polymer in the form of electron addition (i.e., n-doping) or removal (i.e., p-doping).

N-doping is much less common because the Earth's atmosphere is oxygen-rich, thus creating an oxidizing environment. An electron-rich, n-doped polymer will react immediately with elemental oxygen to de-dope (i.e., reoxidize to the neutral state) the polymer. Thus, chemical n-doping must be performed in an environment of inert gas (e.g., argon). Electrochemical n-doping is far more common in research, because it is easier to exclude oxygen from a solvent in a sealed flask. However, it is unlikely that n-doped conductive polymers are available commercially.

Doping in organic molecular semiconductors

Molecular dopants are preferred in doping molecular semiconductors due to their compatibilities of processing with the host, that is, similar evaporation temperatures or controllable solubility.^[24] Additionally, the relatively large sizes of molecular dopants compared with those of metal ion dopants (such as Li⁺ and Mo⁶⁺) are generally beneficial, yielding excellent spatial confinement for use in multilayer structures, such as OLEDs and Organic solar cells. Typical p-type dopants include F4-TCNQ and Mo(tfd)₃. However, similar to the problem encountered in doping conductive polymers, air-stable n-dopants suitable for materials with low electron affinity (EA) are still elusive. Recently, photoactivation with a combination of cleavable dimeric dopants, such as [RuCp^∗Mes]₂, suggests a new path to realize effective n-doping in low-EA materials.

Magnetic doping

Research on magnetic doping has shown that considerable alteration of certain properties such as specific heat may be affected by small concentrations of an impurity; for example, dopant impurities in semiconducting ferromagnetic alloys can generate different properties as first predicted by White, Hogan, Suhl and Nakamura. The inclusion of dopant elements to impart dilute magnetism is of growing significance in the field of Magnetic semiconductors. The presence of disperse ferromagnetic species is key to the functionality of emerging Spintronics, a class of systems that utilise electron spin in addition to charge. Using Density functional theory(DFT) the temperature dependent magnetic behaviour of dopants within a given lattice can be modeled to identify candidate semiconductor systems.

Single dopants in semiconductors

The sensitive dependence of a semiconductor's properties on dopants has provided an extensive range of tunable phenomena to explore and apply to devices. It is possible to identify the effects of a solitary dopant on commercial device performance as well as on the fundamental properties of a semiconductor material. New applications have become available that require the discrete character of a single dopant, such as single-spin devices in the area of quantum information or single-dopant transistors. Dramatic advances in the past decade towards observing, controllably creating and manipulating single dopants, as well as their application in novel devices have allowed opening the new field of solotronics (solitary dopant optoelectronics).

Neutron transmutation doping

Neutron transmutation doping (NTD) is an unusual doping method for special applications. Most commonly, it is used to dope silicon n-type in high-power electronics. It is based on the conversion of the Si-30 isotope into phosphorus atom by neutron absorption as follows:

${\displaystyle ^{30}\mathrm {Si} \,(n,\gamma )\,^{31}\mathrm {Si} \rightarrow \,^{31}\mathrm {P} +\beta ^{-}\;(\mathrm {T} _{1/2}=2.62h).}$

In practice, the silicon is typically placed near a nuclear reactor to receive the neutrons. As neutrons continue to pass through the silicon, more and more phosphorus atoms are produced by transmutation, and therefore the doping becomes more and more strongly n-type. NTD is a far less common doping method than diffusion or ion implantation, but it has the advantage of creating an extremely uniform dopant distribution.

Modulation doping

Modulation doping is a synthesis technique in which the dopants are spatially separated from the carriers. In this way, carrier-donor scattering is suppressed, allowing very high mobility to be attained.

Ambient intelligence

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Ambient_intelligence

 

An (expected) evolution of computing from 1960–2010

In computing, ambient intelligence (AmI) refers to electronic environments that are sensitive and responsive to the presence of people. Ambient intelligence is a vision on the future of consumer electronics, telecommunications and computing that was originally developed in the late 1990s by Eli Zelkha and his team at Palo Alto Ventures for the time frame 2010–2020. In an ambient intelligence world, devices work in concert to support people in carrying out their everyday life activities, tasks and rituals in an easy, natural way using information and intelligence that is hidden in the network connecting these devices (for example: The Internet of Things). As these devices grow smaller, more connected and more integrated into our environment, the technology disappears into our surroundings until only the user interface remains perceivable by users.

The ambient intelligence paradigm builds upon pervasive computing, ubiquitous computing, profiling, context awareness, and human-centric computer interaction design, of which, is characterized by systems and technologies that are:

• embedded: many networked devices are integrated into the environment
• context aware: these devices can recognize you and your situational context
• personalized: they can be tailored to your needs
• adaptive: they can change in response to you
• anticipatory: they can anticipate your desires without conscious mediation.

A typical context of ambient intelligence environment is home, but may also be extended to work spaces (offices, coworking), public spaces (based on technologies such as smart street lights), and hospital environments.

 

 

Overview

More and more people make decisions based on the effect their actions will have on their own inner, mental world. This experience-driven way of acting is a change from the past when people were primarily concerned about the use value of products and services, and is the basis for the experience economy. Ambient intelligence addresses this shift in existential view by emphasizing people and user experience. 

The interest in user experience also grew in importance in the late 1990s because of the overload of products and services in the information society that were difficult to understand and hard to use. An urge emerged to design things from a user's point of view. Ambient intelligence is influenced by user-centered design where the user is placed in the center of the design activity and asked to give feedback through specific user evaluations and tests to improve the design or even co-create the design with the designer (participatory design) or with other users (end-user development).

In order for AmI to become a reality a number of key technologies are required:

• Unobtrusive hardware (miniaturization, nanotechnology, smart devices, sensors etc.)
• Seamless mobile/fixed communication and computing infrastructure (interoperability, wired and wireless networks, service-oriented architecture, semantic web etc.)
• Dynamic and massively distributed device networks, which are easy to control and program (e.g. service discovery, auto-configuration, end-user programmable devices and systems etc.)
• Human-centric computer interfaces (intelligent agents, multimodal interaction, context awareness etc.)
• Dependable and secure systems and devices (self-testing and self repairing software, privacy ensuring technology etc.)

History and invention

In 1998, the board of management of Philips commissioned a series of presentations and internal workshops, organized by Eli Zelkha and Brian Epstein of Palo Alto Ventures (who, with Simon Birrell, coined the term 'ambient intelligence') to investigate different scenarios that would transform the high-volume consumer electronic industry from the current "fragmented with features" world into a world in 2020 where user-friendly devices support ubiquitous information, communication and entertainment. While developing the ambient intelligence concept, Palo Alto Ventures created the keynote address for Roel Pieper of Philips for the Digital Living Room Conference, 1998. The group included Eli Zelkha, Brian Epstein, Simon Birrell, Doug Randall, and Clark Dodsworth. In the years after, these developments grew more mature. In 2005, Philips joined the Oxygen alliance, an international consortium of industrial partners within the context of the MIT Oxygen project, aimed at developing technology for the computer of the 21st century. In 2000, plans were made to construct a feasibility and usability facility dedicated to ambient intelligence. This HomeLab officially opened on 24 April 2002.

Along with the development of the vision at Philips, a number of parallel initiatives started to explore ambient intelligence in more detail. Following the advice of the Information Society and Technology Advisory Group (ISTAG), the European Commission used the vision for the launch of their sixth framework (FP6) in Information, Society and Technology (IST), with a subsidiary budget of 3.7 billion euros. The European Commission played a crucial role in the further development of the AmI vision. As a result of many initiatives the AmI vision gained traction. During the past few years several major initiatives have been started. Fraunhofer Society started several activities in a variety of domains including multimedia, microsystems design and augmented spaces. MIT started an ambient intelligence research group at their Media Lab. Several more research projects started in a variety of countries such as the US, Canada, Spain, France and the Netherlands. Since 2004, the European Symposium on Ambient Intelligence (EUSAI) and many other conferences have been held that address special topics in AmI.

Criticism

As far as dissemination of information on personal presence is out of control, ambient intelligence vision is subject of criticism (e.g. David Wright, Serge Gutwirth, Michael Friedewald et al., Safeguards in a World of Ambient Intelligence, Springer, Dordrecht, 2008). Any immersive, personalized, context-aware and anticipatory characteristics brings up societal, political and cultural concerns about the loss of privacy. The example scenario above shows both the positive and negative possibilities offered by ambient intelligence. Applications of ambient intelligence do not necessarily have to reduce privacy in order to work.

Power concentration in large organizations, a fragmented, decreasingly private society and hyperreal environments where the virtual is indistinguishable from the real are the main topics of critics. Several research groups and communities are investigating the socioeconomic, political and cultural aspects of ambient intelligence. New thinking on AmI distances itself therefore from some of the original characteristics such as adaptive and anticipatory behaviour and emphasizes empowerment and participation to place control in the hands of people instead of organizations.

Social and political aspects

The ISTAG advisory group suggests that the following characteristics will permit the societal acceptance of ambient intelligence. 

AmI should...

• facilitate human contact.
• be oriented towards community and cultural enhancement.
• help to build knowledge and skills for work, better quality of work, citizenship and consumer choice.
• inspire trust and confidence.
• be consistent with long term sustainability—personal, societal and environmental—and with lifelong learning.
• be made easy to live with and controllable by ordinary people.

Business models

The ISTAG group acknowledges the following entry points to AmI business landscape:

• Initial premium value niche markets in industrial, commercial or public applications where enhanced interfaces are needed to support human performance in fast moving or delicate situations.
• Start-up and spin-off opportunities from identifying potential service requirements and putting the services together that meet these new needs.
• High access-low entry cost based on a loss leadership model in order to create economies of scale (mass customization).
• Audience or customer's attention economy as a basis for 'free' end-user services paid for by advertising or complementary services or goods.
• Self-provision—based upon the network economies of very large user communities providing information as a gift or at near zero cost (e.g. social networking applications).
• The combination of multiple and diverse datasets in a platform for sense-making and understanding consumer behaviour (e.g. Near).

Technologies

A variety of technologies can be used to enable Ambient intelligence environments such as (Gasson & Warwick 2007):

• Bluetooth Low Energy
• RFID
• Microchip implant
• Sensors: Ambient light sensor (photodetector), thermometers, proximity sensors and motion detectors
• Software agents
• Affective computing
• Nanotechnology
• Biometrics

Computing

This means of computing links all pieces of technology together. This also allows the device to have the capability to remember past requests.

Uses in fiction

• Minority Report (2002 film). One scene illustrates adaptive advertising in the future: consumers are identified via retinal scans, and receive targeted ads (Parker 2002).
• The Hitchhiker's Guide to the Galaxy by Douglas Adams. The doors have emotion, and express this when people use them.
• The Diamond Age by Neal Stephenson, depicts a world completely changed by the full development of nanotechnology that is present everywhere.
• Her (2013 film). The opening scene depicts the protagonist commuting home, upon arriving the various lights throughout the apartment are turned on as the character moves through the rooms (automated lighting control). A later scene shows that an artificial entity can also control these systems, changing a song being played in the background to lighten a situation, and for humorous effect.

Microchip implant (animals + humans)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Microchip_implant_(animal)

https://en.wikipedia.org/wiki/Microchip_implant_(human)

 

Microchip implant in a cat.

 

A microchip implant is an identifying integrated circuit placed under the skin of an animal. The chip, about the size of a large grain of rice, uses passive radio-frequency identification (RFID) technology, and is also known as a PIT (passive integrated transponder) tag. Standard pet microchips are typically 11-13 mm long (approximately ​¹⁄₂ inch) and 2 mm in diameter.

Externally attached microchips such as RFID ear tags are commonly used to identify farm and ranch animals, with the exception of horses. Some external microchips can be read with the same scanner used with implanted chips.

Uses and benefits

Animal shelters, animal control officers and veterinarians routinely look for microchips to return lost pets quickly to their owners, avoiding expenses for housing, food, medical care, outplacing and euthanasia. Many shelters place chips in all outplaced animals. 

Microchips are also used by kennels, breeders, brokers, trainers, registries, rescue groups, humane societies, clinics, farms, stables, animal clubs and associations, researchers, and pet stores.

Some pet doors can be programmed to be activated by the microchips of specific animals, allowing only certain animals to use the door.

Some countries require microchips in imported animals to match vaccination records. Microchip tagging may also be required for CITES-regulated international trade in certain endangered animals: for example, Asian Arowana are tagged to limit import to captive-bred fish. Also, birds not banded who cross international borders as pets or for trade must be microchipped so that each bird is uniquely identifiable.

Usage

Information about the implant is often imprinted on a collar tag worn by a pet

 

Microchips can be implanted by a veterinarian or at a shelter. After checking that the animal does not already have a chip, the vet or technician injects the chip with a syringe and records the chip's unique ID. No anesthetic is required it is a simple procedure and causes little discomfort: the pain is minimal and short-lived. Studies on horses show swelling and increased sensitivity take approximately three days to resolve. Humans report swelling and bruising at the time of implant, two to four weeks for scar tissue to form and itching and pinching sensations for up to two years. A test scan ensures correct operation. 

Some shelters and vets designate themselves as the primary contact to remain informed about possible problems with the animals they place. The form is sent to a registry, who may be the chip manufacturer, distributor or an independent entity such as a pet recovery service. Some countries have a single official national database. For a fee, the registry typically provides 24-hour, toll-free telephone service for the life of the pet. Some veterinarians leave registration to the owner, usually done online, but a chip without current contact information is essentially useless.

The owner receives a registration certificate with the chip ID and recovery service contact information. The information can also be imprinted on a collar tag worn by the animal. Like an automobile title, the certificate serves as proof of ownership and is transferred with the animal when it is sold or traded; an animal without a certificate could be stolen. Nevertheless, there are some privacy concerns regarding the use of microchips.

Authorities and shelters examine strays for chips, providing the recovery service with the ID number, description and location so they may notify the owner or contact. If the pet is wearing the collar tag, the finder does not need a chip reader to contact the registry. An owner can also report a missing pet to the recovery service, as vets look for chips in new animals and check with the recovery service to see if it has been reported lost or stolen.

Many veterinarians scan an animal's chip on every visit to verify correct operation. Some use the chip ID as their database index and print it on receipts, test results, vaccination certifications and other records.

Some veterinary tests and procedures require positive identification of the animal, and a microchip may be acceptable for this purpose as an alternative to a tattoo.

Components of a microchip

A microchip implant is a passive RFID device. Lacking an internal power source, it remains inert until it is powered by the scanner or another power source. While the chip itself only interacts with limited frequencies, the device also has an antenna that is optimized for a specific frequency, but is not selective. It may receive, generate current with, and reradiate stray electromagnetic waves.

Most implants contain three elements: a 'chip' or integrated circuit; a coil inductor, possibly with a ferrite core; and a capacitor. The chip contains unique identification data and electronic circuits to encode that information. The coil acts as the secondary winding of a transformer, receiving power inductively coupled to it from the scanner. The coil and capacitor together form a resonant LC circuit tuned to the frequency of the scanner's oscillating magnetic field to produce power for the chip. The chip then transmits its data back through the coil to the scanner. The way the chip communicates with the scanner is a method called backscatter. It becomes part of the electromagnetic field and modulates it in a manner that communicates the ID number to the scanner.

Example of an RFID scanner used with animal microchip implants.

 

These components are encased in biocompatible soda lime or borosilicate glass and hermetically sealed. Leaded glass should not be used for pet microchips and consumers should only accept microchips from reliable sources. The glass is also sometimes coated with polymers. Parylene C (chlorinated poly-dimethylbenzene) has become a common coating. Plastic pet microchips have been registered in the international registry since 2012 under Datamars manufacturer code 981 and are being implanted in pets. The patent suggests it is a silicon filled polyester sheath, but the manufacturer does not disclose the exact composition.

Implant location

In dogs and cats, chips are usually inserted below the skin at the back of the neck between the shoulder blades on the dorsal midline. According to one reference, continental European pets get the implant in the left side of the neck. The chip can often be felt under the skin. Thin layers of connective tissue form around the implant and hold it in place.

Horses are microchipped on the left side of the neck, halfway between the poll and withers and approximately one inch below the midline of the mane, into the nuchal ligament. 

Birds are implanted in their breast muscles. Proper restraint is necessary so the operation requires either two people (an avian veterinarian and a veterinary technician) or general anesthesia. 

Animal species

Horse microchipping

Many animal species have been microchipped, including cockatiels and other parrots, horses, llamas, alpacas, goats, sheep, miniature pigs, rabbits, deer, ferrets, penguins, sharks, snakes, lizards, alligators, turtles, toads, frogs, rare fish, chimpanzees, mice, and prairie dogs—even whales and elephants. The U.S. Fish and Wildlife Service uses microchipping in its research of wild bison, black-footed ferrets, grizzly bears, elk, white-tailed deer, giant land tortoises and armadillos.

Worldwide use

Microchips are not yet universal, but they are legally required in some jurisdictions such as the state of New South Wales, Australia and the United Kingdom (for dogs, since 6 April 2016).

Some countries, such as Japan, require ISO-compliant microchips or a compatible reader on imported dogs and cats.

In New Zealand, all dogs first registered after 1 July 2006 must be microchipped. Farmers protested that farm dogs should be exempt, drawing a parallel to the Dog Tax War of 1898. Farm dogs were exempted from microchipping in an amendment to the legislation passed in June 2006. A National Animal Identification and Tracing scheme in New Zealand is currently being developed for tracking livestock.

In April 2012 Northern Ireland became the first part of the United Kingdom to require microchipping of individually licensed dogs. Dog microchipping became mandatory in England on 6 April 2016.

In Israel, microchips in dogs are mandatory.

Australia has a National Livestock Identification System. 

The United States uses the National Animal Identification System for farm and ranch animals other than dogs and cats. In most species except horses, an external eartag is typically used in lieu of an implant microchip. Eartags with microchips or simply stamped with a visible number can be used. Both use ISO fifteen-digit microchip numbers with the U.S. country code of 840.

Cross-compatibility and standards issues

In most countries, pet ID chips adhere to an international standard to promote compatibility between chips and scanners. In the United States, however, three proprietary types of chips compete along with the international standard. Scanners distributed to United States shelters and veterinarians well into 2006 could each read at most three of the four types. Scanners with quad-read capability are now available and are increasingly considered required equipment. Older scanner models will be in use for some time, so United States pet owners must still choose between a chip with good coverage by existing scanners and one compatible with the international standard. The four types include:

• The ISO conformant full-duplex type has the greatest international acceptance. It is common in many countries including Canada and large parts of Europe (since the late 1990s). It is one of two chip protocol types (along with the "half-duplex" type sometimes used in farm and ranch animals) that conform to International Organization for Standardization standards ISO 11784 and ISO 11785. To support international/multivendor application, the three-digit country code can contain an assigned ISO country code or a manufacturer code from 900 to 998 plus its identifying serial number. In the United States, distribution of this type has been controversial. When 24PetWatch.com began distributing them in 2003 (and more famously Banfield Pet Hospitals in 2004) many shelter scanners couldn't read them. At least one Banfield-chipped pet was inadvertently euthanized.
• The Trovan Unique type is another pet chip protocol type in use since 1990 in pets in the United States. Patent problems forced the withdrawal of Trovan's implanter device from United States distribution and they became uncommon in pets in the United States, although Trovan's original registry database "infopet.biz" remained in operation. In early 2007, the American Kennel Club's chip registration service, AKC Companion Animal Recovery Corp, which had been the authorized registry for HomeAgain brand chips made by Destron/Digital Angel, began distributing Trovan chips with a different implanter. These chips are read by the Trovan, HomeAgain (Destron Fearing), and Bayer (Black Label) readers. Despite multiple offers from Trovan to AVID to license the technology to read the Trovan chips, AVID continues to distribute readers that do not read Trovan or the ISO compliant chips.
• A third type, sometimes known as FECAVA or Destron, is available under various brand names. These include, in the United States, "Avid Eurochip", the common current 24PetWatch chips, and the original (and still popular) style of HomeAgain chips. (HomeAgain and 24Petwatch can now supply the true ISO chip instead on request.) Chips of this type have ten-digit hexadecimal chip numbers. This "FECAVA" type is readable on a wide variety of scanners in the United States and has been less controversial, although its level of adherence to the ISO standards is sometimes exaggerated in some descriptions. The ISO standard has an annex (appendix) recommending that three older chip types be supported by scanners, including a 35-bit "FECAVA"/"Destron" type. The common Eurochip/HomeAgain chips don't agree perfectly with the annex description, although the differences are sometimes considered minor. But the ISO standard also makes it clear that only its 64-bit "full-duplex" and "half-duplex" types are "conformant"; even chips (e.g., the Trovan Unique) that match one of the Annex descriptions are not. More visibly, FECAVA cannot support the ISO standard's required country/manufacturer codes. They may be accepted by authorities in many countries where ISO-standard chips are the norm, but not by those requiring literal ISO conformance.
• Finally, there's the AVID brand Friendchip type, which is peculiar due to its encryption characteristics. Cryptographic features are not necessarily unwelcome; few pet rescuers or humane societies would object to a design that outputs an ID number "in the clear" for anyone to read, along with authentication features for detection of counterfeit chips, but the authentication in "Friendchips" has been found lacking and rather easy to spoof to the AVID scanner. Although no authentication encryption is involved, obfuscation requires proprietary information to convert transmitted chip data to its original label ID code. Well into 2006, scanners containing the proprietary decryption were provided to the United States market only by AVID and Destron/Digital Angel; Destron/Digital Angel put the decryption feature in some, but not all, of its scanners, possibly as early as 1996. (For years, its scanners distributed to shelters through HomeAgain usually had full decryption, while many sold to veterinarians would only state that an AVID chip had been found.) Well into 2006, both were resisting calls from consumers and welfare group officials to bring scanners to the United States shelter community combining AVID decryption capability with the ability to read ISO-compliant chips. Some complained that AVID itself had long marketed combination pet scanners compatible with all common pet chips except possibly Trovan outside the United States. By keeping them out of the United States, it could be considered partly culpable in the missed-ISO chips problem others blamed on Banfield. In 2006, the European manufacturer Datamars, a supplier of ISO chips used by Banfield and others, gained access to the decryption secrets and began supplying scanners with them to United States customers. This "Black Label" scanner was the first four-standard full-multi pet scanner in the United States market. Later in 2006, Digital Angel announced that it would supply a full-multi scanner in the United States. In 2008 AVID announced a "breakthrough" scanner, although as of October 2010 AVID's is still so uncommon that it's unclear whether it supports the Trovan chip. Trovan also acquired the decryption technology in 2006 or earlier, and now provides it in scanners distributed in the United States by AKC-CAR. (Some are quad-read, but others lack full ISO support.)

Numerous references in print state that the incompatibilities between different chip types are a matter of "frequency". One may find claims that early ISO adopters in the United States endangered their customers' pets by giving them ISO chips that work at a "different frequency" from the local shelter's scanner, or that the United States government considered forcing an incompatible frequency change. These claims were little challenged by manufacturers and distributors of ISO chips, although later evidence suggests the claims were disinformation. In fact, all chips operate at the scanner's frequency. Although ISO chips are optimized for 134.2 kHz, in practice they are readable at 125 kHz and the "125 kHz" chips are readable at 134.2 kHz. Confirmation comes from government filings that indicate the supposed "multi-frequency" scanners now commonly available are really single-frequency scanners operating at 125, 134.2 or 128 kHz. In particular, the United States HomeAgain scanner didn't change excitation frequency when ISO-read capability was added; it's still a single frequency, 125 kHz scanner.

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Microchip implant (human)

A surgeon implants British scientist Dr Mark Gasson in his left hand with an RFID microchip (March 16, 2009)

A human microchip implant is typically an identifying integrated circuit device or RFID transponder encased in silicate glass and implanted in the body of a human being. This type of subdermal implant usually contains a unique ID number that can be linked to information contained in an external database, such as personal identification, law enforcement, medical history, medications, allergies, and contact information. 

History

The first experiments with a radio-frequency identification (RFID) implant were carried out in 1998 by the British scientist Kevin Warwick. His implant was used to open doors, switch on lights, and cause verbal output within a building. After nine days the implant was removed and has since been held in the Science Museum in London.

In early March 2005 hobbyist Amal Graafstra implanted a 125khz EM4102 bioglass-encased RFID transponder into his left hand. It was used with an access control system to gain entry to his office. Soon after in June 2005 he implanted a more advanced HITAG S 2048 low frequency transponder. In 2007 he authored the book RFID Toys, Graafstra uses his implants to access his home, open car doors, and to log on to his computer. With public interest growing, in 2013 he launched biohacking company Dangerous Things and crowdfunded the world's first implantable NFC transponder in 2014. He has also spoken at various events and promotional gigs including TEDx, and built a smartgun that only fires after reading his implant.

On 16 March 2009 British scientist Mark Gasson had a glass capsule RFID device surgically implanted into his left hand. In April 2010 Gasson's team demonstrated how a computer virus could wirelessly infect his implant and then be transmitted on to other systems. Gasson reasoned that with implanted technology the separation between man and machine can become theoretical because the technology can be perceived by the human as being a part of their body. Because of this development in our understanding of what constitutes our body and its boundaries he became credited as being the first human infected by a computer virus. He has no plans to remove his implant.

Hobbyists

An RFID tag visible under the skin soon after being implanted.

 

Several hobbyists have placed RFID microchip implants into their hands or had them inserted by others.

Alejandro Hernandez CEO of Futura is known to be the first in Central America to have a Dangerous Things transponder installed in his left hand by Federico Cortes in November 2017.

Mikey Sklar had a chip implanted into his left hand and filmed the procedure.

Jonathan Oxer self-implanted an RFID chip in his arm using a veterinary implantation tool.

Martijn Wismeijer, Dutch marketing manager for Bitcoin ATM manufacturer General Bytes, placed RFID chips in both of his hands to store his Bitcoin private keys and business card.

Patric Lanhed sent a “bio-payment” of one euro worth of Bitcoin using a chip embedded in his hand.

Marcel Varallo had an NXP chip coated in Bioglass 8625 inserted into his hand between his forefinger and thumb allowing him to open secure elevators and doors at work, print from secure printers, unlock his mobile phone and home, and store his digital business card for transfer to mobile phones enabled for NFC.

Biohacker Hannes Sjöblad has been experimenting with near field communication (NFC) chip implants since 2015. During his talk at Echappée Voléé 2016 in Paris, Sjöblad disclosed that he has also implanted himself between his forefinger and thumb and uses it to unlock doors, make payments, and unlock his phone (essentially replacing anything you can put in your pockets). Additionally, Sjöblad has hosted several "implant parties," where interested individuals can also be implanted with the chip.

Commercial implants

Digital identity

VivoKey Technologies developed the first cryptographically-secure human implantable NFC transponders in 2018. The Spark is an AES128 bit capable ISO/IEC 15693 2mm by 12mm bioglass encased injectable device. The Flex One is an implantable contactless secure element, capable of running Java Card applets (software programs) including Bitcoin wallets, PGP, OATH OTP, U2F, WebAuthn, etc. It is encapsulated in a flat, flexible 7mm x 34mm x 0.4mm flat biopolymer shell. Applets can be deployed to the Flex One before or after implantation. 

Medical records

Researchers have examined microchip implants in humans in the medical field and they indicate that there are potential benefits and risks to incorporating the device in the medical field. For example, it could be beneficial for noncompliant patients but still poses great risks for potential misuse of the device.

Destron Fearing, a subsidiary of Digital Angel, initially developed the technology for the VeriChip.

In 2004, the VeriChip implanted device and reader were classified as Class II: General controls with special controls by the FDA; that year the FDA also published a draft guidance describing the special controls required to market such devices.

About the size of a grain of rice, the device was typically implanted between the shoulder and elbow area of an individual’s right arm. Once scanned at the proper frequency, the chip responded with a unique 16-digit number which could be then linked with information about the user held on a database for identity verification, medical records access and other uses. The insertion procedure was performed under local anesthetic in a physician's office.

Privacy advocates raised concerns regarding potential abuse of the chip, with some warning that adoption by governments as a compulsory identification program could lead to erosion of civil liberties, as well as identity theft if the device should be hacked. Another ethical dilemma posed by the technology, is that people with dementia could possibly benefit the most from an implanted device that contained their medical records, but issues of informed consent are the most difficult in precisely such people.

In June 2007, the American Medical Association declared that "implantable radio frequency identification (RFID) devices may help to identify patients, thereby improving the safety and efficiency of patient care, and may be used to enable secure access to patient clinical information", but in the same year, news reports linking similar devices to cancer caused in laboratory animals had a devastating impact on the company's stock price and sales.

In 2010, the company, by then called PositiveID, withdrew the product from the market due to poor sales.

In January 2012, PositiveID sold the chip assets to a company called VeriTeQ that was owned by Scott Silverman, the former CEO of Positive ID.

In 2016, JAMM Technologies acquired the chip assets from VeriTeQ; JAMM's business plan was to partner with companies selling implanted medical devices and use the RfID tags to monitor and identify the devices. JAMM Technologies is co-located in the same Plymouth, Minnesota building as Geissler Corporation with Randolph K. Geissler and Donald R. Brattain listed as its principals. The website also claims that Geissler was CEO of PositiveID Corporation, Destron Fearing Corporation, and Digital Angel Corporation.

In 2018, A Danish firm called BiChip released a new generation of microchip implant that is intended to be readable from distance and connected to Internet. The company released an update for its microchip implant to associate it with the Ripple cryptocurrency to allow payments to be made using the implanted microchip.

Building access and security

In February 2006, CityWatcher, Inc. of Cincinnati, OH became the first company in the world to implant microchips into their employees as part of their building access control and security system. The workers needed the implants to access the company's secure video tape room, as documented in USA Today. The project was initiated and implemented by Six Sigma Security, Inc. The VeriChip Corporation had originally marketed the implant as a way to restrict access to secure facilities such as power plants.

A major drawback for such systems is the relative ease with which the 16-digit ID number contained in a chip implant can be obtained and cloned using a hand-held device, a problem that has been demonstrated publicly by security researcher Jonathan Westhues and documented in the May 2006 issue of Wired magazine, among other places.

• The Baja Beach Club, a nightclub in Rotterdam, the Netherlands, once used VeriChip implants for identifying VIP guests.
• The Epicenter in Stockholm, Sweden is using RFID implants for employees to operate security doors, copiers, and pay for lunch.

Possible future applications

In 2017 Mike Miller, chief executive of the World Olympians Association, was widely reported as suggesting the use of such implants in athletes in an attempt to reduce problems in sport due to drug taking.

Theoretically, a GPS-enabled chip could one day make it possible for individuals to be physically located by latitude, longitude, altitude, and velocity. Such implantable GPS devices are not technically feasible at this time. However, if widely deployed at some future point, implantable GPS devices could conceivably allow authorities to locate missing persons and/or fugitives and those who fled from a crime scene. Critics contend, however, that the technology could lead to political repression as governments could use implants to track and persecute human rights activists, labor activists, civil dissidents, and political opponents; criminals and domestic abusers could use them to stalk and harass their victims; and child abusers could use them to locate and abduct children.

Another suggested application for a tracking implant, discussed in 2008 by the legislature of Indonesia's Irian Jaya would be to monitor the activities of persons infected with HIV, aimed at reducing their chances of infecting other people. The microchipping section was not, however, included into the final version of the provincial HIV/AIDS Handling bylaw passed by the legislature in December 2008. With current technology, this would not be workable anyway, since there is no implantable device on the market with GPS tracking capability.

Since modern payment methods rely upon RFID/NFC, it is thought that implantable microchips, if they were to ever become popular in use, would form a part of the cashless society. Verichip implants have already been used in nightclubs such as the Baja club for such a purpose, allowing patrons to purchase drinks with their implantable microchip. 

Anti-Rhetoric Claims

Cancer

In a self-published report anti-RFID advocate Katherine Albrecht, who refers to RFID devices as "spy chips", cites veterinary and toxicological studies carried out from 1996 to 2006 which found lab rodents injected with microchips as an incidental part of unrelated experiments and dogs implanted with identification microchips sometimes developed cancerous tumors at the injection site (subcutaneous sarcomas) as evidence of a human implantation risk. However, the link between foreign-body tumorigenesis in lab animals and implantation in humans has been publicly refuted as erroneous and misleading and the report's author has been criticized over the use of "provocative" language "not based in scientific fact". Notably, none of the studies cited specifically set out to investigate the cancer risk of implanted microchips and so none of the studies had a control group of animals that did not get implanted. While the issue is considered worthy of further investigation, one of the studies cited cautioned "Blind leaps from the detection of tumors to the prediction of human health risk should be avoided".

Security risks

The Council on Ethical and Judicial Affairs (CEJA) of the American Medical Association published a report in 2007 alleging that RFID implanted chips may compromise privacy because there is no assurance that the information contained in the chip can be properly protected.

Legislation

United States

Following Wisconsin and North Dakota, California issued Senate Bill 362 in 2007, which makes it illegal to force a person to have a microchip implanted, and provide for an assessment of civil penalties against violators of the bill.

In 2008, Oklahoma passed 63 OK Stat § 63-1-1430 (2008 S.B. 47), that bans involuntary microchip implants in humans.

On April 5, 2010, the Georgia Senate passed Senate Bill 235 that prohibits forced microchip implants in humans and that would make it a misdemeanor for anyone to require them, including employers. The bill would allow voluntary microchip implants, as long as they are performed by a physician and regulated by the Georgia Composite Medical Board. The state's House of Representatives did not take up the measure.

On February 10, 2010, Virginia's House of Delegates also passed a bill that forbids companies from forcing their employees to be implanted with tracking devices.

Washington State House Bill 1142-2009-10 orders a study using implanted radio frequency identification or other similar technology to electronically monitor sex offenders and other felons.

In popular culture

The general public are most familiar with microchips in the context of tracking their pets. In the U.S., some Christian activists, including conspiracy theorist Mark Dice, the author of a book titled The Resistance Manifesto, make a link between the PositiveID and the Biblical Mark of the Beast, prophesied to be a future requirement for buying and selling, and a key element of the Book of Revelation. Gary Wohlscheid, president of These Last Days Ministries, has argued that "Out of all the technologies with potential to be the mark of the beast, VeriChip has got the best possibility right now". "Arkangel", an episode of the fictional drama series Black Mirror, considered the potential for helicopter parenting of an imagined more advanced microchip.