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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 ...
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.
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.
In semiconductor physics, an acceptor is a dopant atom that when substituted into a semiconductor lattice forms a p-type region. Boron atom acting as an acceptor in the simplified 2D silicon lattice. When silicon (Si), having four valence electrons , is doped with elements from group III of the periodic table , such as boron (B) and aluminium ...
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 ...
This allows us to treat the original semiconductor as unaffected in its electronic properties, with the impurity atoms only increasing the electron concentration. A limit to donor concentration in order to allow treatment as shallow donors is approximately 10 19 cm −3. Energy levels due to impurities deeper in the bandgap are called deep levels.