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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.
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 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 ...
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 ...
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.
An extrinsic semiconductor is one that has been doped; during manufacture of the semiconductor crystal a trace element or chemical called a doping agent has been incorporated chemically into the crystal, for the purpose of giving it different electrical properties than the pure semiconductor crystal, which is called an intrinsic semiconductor.
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.
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 ...