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Topic: Doping (semiconductor)

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In the News (Wed 22 May 19)

  Doping Information - semiconductor doping
The semiconductor doping number of dopant atoms athlete doping scandals needed to create a difference in the ability of a semiconductor to conduct is very small.
By doping pure silicon with group V elements such as Phosphorus, tour de france speeds and doping extra valence electrons are added which become unbonded from individual atoms lance armstrong blood doping in sports doping and allow the compound to be electrically conductive, n-type material.
Doping with group III elements, such as Boron, which are missing lance armstrong doping allegations the forth valence electron creates "broken bonds", or holes, in the silicon lattice that are free lance zivilrechtliche haftung im doping armstrong's doctors and doping to move.
www.inanot.com /Ina-Electronics_Topics_D-/Doping.html   (971 words)

 Doping (semiconductor) - Wikipedia, the free encyclopedia
By doping pure silicon with group V elements such as phosphorus, extra valence electrons are added which become unbonded from individual atoms and allow the compound to be electrically conductive, n-type material.
Doping with group III elements, such as boron, which are missing the fourth valence electron creates "broken bonds", or holes, in the silicon lattice that are free to move.
The second is electrochemical doping in which a polymer-coated, working electrode is suspended in an electrolyte solution in which the polymer is insoluble along with separate counter and reference electrodes.
en.wikipedia.org /wiki/Doping_(semiconductors)   (836 words)

 NFM - Semiconductor
Semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor.
A semiconductor has a band gap which is small enough such that its conduction band is appreciably thermally populated with electrons at room temperature, whilst an insulator has a band gap which is too wide for there to be appreciable thermal electrons in its conduction band at room temperature.
It also follows from this that minority carrier concentrations in doped semiconductors are dependent on temperature to the square of the extent that carrier concentrations in intrinsic semiconductors are, since the majority carrier concentration is effectively fixed at the doping level.
nanofm.com /terms/semiconductor.html   (1815 words)

 Impurities. Crystal doping
The purpose of semiconductor doping is to increase the number of free charges that can be moved by an external applied voltage.
Doping is the process by which engineers change an insulating material into a semiconductor.
The effect of doping is to provide the bulk material with a population of free electrons which have been donated by - the dopant.
www.mtmi.vu.lt /pfk/funkc_dariniai/sol_st_phys/impurities.htm   (1219 words)

 Semiconductor - Wikipedia, the free encyclopedia
Semiconductor devices are essential in modern electrical devices, from computers to cellular phones to digital audio players.
Semiconductors may be elemental materials such as silicon and germanium, or compound semiconductors such as gallium arsenide and indium phosphide, or alloys such as silicon germanium or aluminium gallium arsenide.
In manufacturing semiconductor devices involving heterojunctions between different semiconductor materials, the lattice constant, which is the length of the repeating element of the crystal structure, is important for determining the compatibility of materials.
en.wikipedia.org /wiki/Semiconductor   (2604 words)

 PartMiner Component Guide (semiconductor reference guide)
Semiconductor devices are available as single discrete devices or as components of an integrated circuit (IC), which consists of a large number–from hundreds to millions–of devices manufactured onto a single semiconductor substrate.
Doping a semiconductor such as silicon with a small amount of impurity atoms, such as phosphorus or boron, greatly increases the number of free electrons or holes (generally known as charge carriers) within the semiconductor.
The semiconductor material used in devices is doped under highly controlled conditions in a "fab" to precisely control the location and concentration of p- and n-type dopants.
components.partminer.com   (254 words)

 Heterostructure semiconductor device - Patent 4755857
The second layer is doped with a conductivity-determining doping material, the doping material concentration in said second layer being at least one order of magnitude larger than the concentration of any doping material present in the first layer.
The semiconductor and doping materials are chosen such that the energy levels of the doping material atoms in the second layer have an energetically more unfavorable position than an adjacent of the energy bands of the first layer, so that charge carriers migrate from the doped second layer into an adjacent region of first layer.
The mobility of the charge carriers is increased in the heterostructure semiconductor bodies and devices according to the invention because the charge carriers are transferred from the relatively heavily doped semiconductor material of the larger band gap into the less doped semiconductor material having the smaller band gap.
www.freepatentsonline.com /4755857.html   (2484 words)

 Doped Semiconductors
The addition of a small percentage of foreign atoms in the regular crystal lattice of silicon or germanium produces dramatic changes in their electrical properties, producing n-type and p-type semiconductors.
The addition of pentavalent impurities such as antimony, arsenic or phosphorous contributes free electrons, greatly increasing the conductivity of the intrinsic semiconductor.
The application of band theory to n-type and p-type semiconductors shows that extra levels have been added by the impurities.
hyperphysics.phy-astr.gsu.edu /hbase/solids/dope.html   (189 words)

 Howstuffworks "How Semiconductors Work"
Semiconductors have had a monumental impact on our society.
You find semiconductors at the heart of microprocessor chips as well as transistors.
The natural progression from silicon to doped silicon to transistors to chips is what has made microprocessors and other electronic devices so inexpensive and ubiquitous in today's society.
electronics.howstuffworks.com /diode.htm   (1209 words)

 Proximity doping of amorphous semiconductors - Patent 4642144
In substitutionally doped amorphous silicon the large density of gap states associated with the dopants means that the depletion or accumulation layers associated with Schottky contacts or externally applied gate voltages are thin in doped material, being of order 500A thick, which is not as thick as would be desirable in field effect transistors.
The second plurality is doped such that the charge carriers in the gap states from the second plurality of layers transfer to the first plurality of layers and cause the conductivity of said first plurality to increase.
In amorphous semiconductors the density of states edges are broader, being broadened by the structural disorder of the amorphous network in addition to the thermal motion of the atoms.
www.freepatentsonline.com /4642144.html   (3944 words)

The addition of dopants to a semiconductor to produce components of semiconductor devices such as transistors and solar cells.
Through doping, a semiconductor material may acquire a surplus of positive charge carriers and become a p-type semiconductor or a surplus of negative charge carriers and become an n-type semiconductor.
If two differently contaminated semiconductor layers are combined, then a so-called p-n junction results on the boundary of the layers.
www.daviddarling.info /encyclopedia/D/AE_doping.html   (128 words)

 The 2006-2011 World Outlook for Parts for Ion Implanters Used for Doping
Depending on original data sources used, the definition of “parts for ion implanters used for doping semiconductor wafers” is established.
It is for this definition of parts for ion implanters used for doping semiconductor wafers that the aggregate latent demand estimates are derived.
Based on the aggregate view of parts for ion implanters used for doping semiconductor wafers as defined above, data were then collected for as many similar countries as possible for that same definition, at the same level of the value chain.
www.mindbranch.com /products/R307-16259.html   (2922 words)

 Research Area: Nanostructures
We are particularly interested in the effects on nanostructures of doping and of variations in the external environment such as temperature, electric field, strain.
Doping semiconductor nanocrystals: Nanocrystals are tiny semiconductor particles just a few millionths of a millimeter across.
Thus, doping is a critical step for tailoring their properties for specific applications.
cst-www.nrl.navy.mil /ResearchAreas/Nanostructures   (1237 words)

 ScienceDaily: Semiconductor   (Site not responding. Last check: 2007-11-04)
UB Engineer Discovers Carbon Composite Is A Semiconductor (March 6, 1998) -- A University at Buffalo engineer has made the first observation of semiconducting behavior in a carbon composite material, a finding that could revolutionize the fields of "smart" structures and...
Optical Electronic Devices Could Benefit From New Semiconductor Standard (October 17, 2006) -- A wide range of optical electronic devices, from laser disk players to traffic lights, may be improved in the future thanks to a small piece of semiconductor, about the size of a button, coated with...
Semiconductor -- A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor.
www.sciencedaily.com /encyclopedia/Semiconductor   (1376 words)

 Bipolar doping   (Site not responding. Last check: 2007-11-04)
Controlled doping of conventional inorganic semiconductors is one of the key technologies contributing to the advance of electronic and optoelectronic devices.
Doping can also reduce the high contact resistance in organic thin-film transistors (OTFTs), and may eventually lead to realization of organic electronic devices, such as bipolar transistors and tunnel diodes, in analogy to inorganic semiconductor devices.
The bipolar doping effect can also be demonstrated through the conductivity increase of the BTQBT and PTCDA films upon doping of the other material, as shown in the figure to the right.
www.princeton.edu /~jxue/research/doping/doping.html   (515 words)

 Print the story
In an example of doped nanocrystals, this charge density plot shows magnesium impurities in cadmium-selenium nanocrystals at two different gap levels: (a) resonant and (b) hybrid.
Doping semiconductor nanocrystals will likely provide a basis for a wide variety of nano applications.
On the macroscale, doping led to the transistor.
www.physorg.com /printnews.php?newsid=70115009   (782 words)

 Ion implantation in silicon technology - The Industrial Physicist
Doping or otherwise modifying silicon and other semiconductor wafers relies on the technology, which involves generating an ion beam and steering it into the substrate so that the ions come to rest beneath the surface.
William Shockley first recognized the potential of ion implantation for doping semiconductor materials, and his 1954 patent application demonstrates a remarkable understanding of the relevant process issues long before implantation entered mass production.
Whereas processing a simple n-type metal oxide semiconductor during the 1970s may have required 6 to 8 implants, a modern complementarymetal- oxide-semiconductor (CMOS) IC with embedded memory may contain up to 35 implants.
www.aip.org /tip/INPHFA/vol-9/iss-3/p12.html   (2118 words)

 p-n Junction
Doping - the addition of 'foreign' atoms to the material.
Two of the equations are series and boundary value problems, which consider the change in the number of carriers as a function of the change of carrier current, and the recombination rate (a non-linear function of n, p).
Ions of the semiconductor together with dopants are fired at the crystal surface.
www.mtmi.vu.lt /pfk/funkc_dariniai/diod   (2687 words)

 2.2.2 Doping and Carrier Concentration
We have now sharp allowed energy energy levels in the band gap, belonging to electrons of the doping atoms, or since electrons can not be distinguished, to all electrons in the semiconductor.
Some data showing the relationship between doping and resisitivity (= 1/conductivity) or the temperature dependence of the conductivity are shown in the illustration.
The deviation from a straight line for lower doping concentrations in the resistivity - temperature plot for is due to the temperature dependence of the mobility.
www.tf.uni-kiel.de /matwis/amat/semi_en/kap_2/backbone/r2_2_2.html   (1486 words)

 Research Area: Quantum Dots
We have shown that doping difficulties are not intrinsic, and indeed are amenable to systematic optimization using straightforward methods from physical chemistry.
The bulk band structure of a typical direct gap semiconductor with cubic or zinc-blende lattice structure and band edge at the Gamma point of the Brillouin zone.
We are also working on methods to calculate the energy spectra and spin-polarization properties of biexcitons in nanocrystal semiconductor structures, which control all the nonlinear optical properties of nanocrystals.
cst-www.nrl.navy.mil /ResearchAreas/QuantumDots   (1015 words)

 Doping in III-V Semiconductors - Cambridge University Press   (Site not responding. Last check: 2007-11-04)
Equal emphasis is given to the fundamental materials physics and to the technological aspects of doping.
The author describes in detail all the various techniques, including doping during epitaxial growth, doping by implantation, and doping by diffusion.
The timely topic of highly doped semiconductors is discussed as well.
www.cambridge.org /catalogue/catalogue.asp?isbn=0521419190   (215 words)

 Discovery of 'doping' mechanism in semiconductor nanocrystals
Nanocrystals are tiny semiconductor particles just a few millionths of a millimeter across.
If the impurity binds to the nanocrystal surface too weakly, or if the strongly binding surfaces are only a small fraction of the total, then doping will be difficult." From calculations based on this central idea, the team could predict conditions favorable for doping.
According to Dr. David Norris, an Associate Professor of Chemical Engineering and Materials Science at UMN and the lead experimentalist on the team, "an exciting aspect of these results is that they overturn a common belief that nanocrystals are intrinsically difficult to dope because they somehow 'self-purify' by expelling impurities from their interior.
www.eurekalert.org /pub_releases/2005-07/nrl-do070705.php   (643 words)

 Carriers - Doping a Semiconductor   (Site not responding. Last check: 2007-11-04)
Doping is a routine process in fabricating semiconductor devices, making them extrinsic semiconductors.
Donors, all from Column V of the periodic table, introduce energy states within the band gap close to the conduction band.
The semiconductor is now p-type, which can be associated with positive carriers.
www.ece.utep.edu /courses/ee3329/ee3329/Studyguide/ToC/Fundamentals/Carriers/dopants.html   (426 words)

 Doping   (Site not responding. Last check: 2007-11-04)
Doping is the addition of controlled amounts of specific impurity atoms for the purpose of changing the conductivity of a semiconductor sample by increasing either the electron or hole concentration.
The fifth electron, however, is weakly bound, and at room temperature is free to move through the crystal (Figure 2a).
It is thus said to be "donated" to the semiconductor.
www.ece.gatech.edu /research/labs/vc/theory/doping.html   (226 words)

While the Semiconductor Device Simulator is designed to enable the student to learn about energy bands in p-n junction devices and how these can be used to explain the electrical and spectral characteristics of these devices, the simulation is not accurate in certain situations.
Indeed, semiconductor materials used to make LEDs are often doped with nitrogen, phosphorous, arsenic etc. to introduce these additional states, and alter their spectral characteristics.
Having appropriately doped each semiconductor block, so that one of them is P type and the other N type, students bring the two semiconductor blocks together by clicking the "Connect" button, and then click the "Equilibrate" button (Figure 3) to make the Fermi levels on the two sides align.
web.phys.ksu.edu /papers/sds/SDSPaper.htm   (7186 words)

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