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Doping of a pure silicon array. Silicon based intrinsic semiconductor becomes extrinsic when impurities such as boron and antimony are introduced.. In semiconductor production, doping is the intentional introduction of impurities into an intrinsic (undoped) semiconductor for the purpose of modulating its electrical, optical and structural properties.
For example, doping pure silicon with a small amount of phosphorus will increase the carrier density of electrons, n. Then, since n > p, the doped silicon will be a n-type extrinsic semiconductor. Doping pure silicon with a small amount of boron will increase the carrier density of holes, so then p > n, and it will be a p-type extrinsic ...
In semiconductor physics, a donor is a dopant atom that, when added to a semiconductor, can form a n-type region. Phosphorus atom acting as a donor in the simplified 2D silicon lattice. For example, when silicon (Si), having four valence electrons , is to be doped as a n-type semiconductor , elements from group V like phosphorus (P) or arsenic ...
However, doping silicon with a pnictogen such as phosphorus, arsenic, or antimony introduces one extra electron per dopant and these may then be excited into the conduction band either thermally or photolytically, creating an n-type semiconductor. Similarly, doping silicon with a group 13 element such as boron, aluminium, or gallium results in ...
In p-type semiconductors, holes are the majority carriers and electrons are the minority carriers. A common p-type dopant for silicon is boron or gallium. For p-type semiconductors the Fermi level is below the intrinsic semiconductor and lies closer to the valence band than the conduction band. Examples: boron, aluminium, gallium, etc.
A degenerate semiconductor is a semiconductor with such a high level of doping that the material starts to act more like a metal than a semiconductor. Unlike non-degenerate semiconductors, these kinds of semiconductor do not obey the law of mass action, which relates intrinsic carrier concentration with temperature and bandgap.
The addition of a dopant to a semiconductor, known as doping, has the effect of shifting the Fermi levels within the material. [ citation needed ] This results in a material with predominantly negative ( n-type ) or positive ( p-type ) charge carriers depending on the dopant variety.
At absolute zero temperature, all of the electrons have energy below the Fermi level; but at non-zero temperatures the energy levels are filled following a Fermi-Dirac distribution. In undoped semiconductors the Fermi level lies in the middle of a forbidden band or band gap between two allowed bands called the valence band and the conduction ...