In-line diode semiconductor dopants

Which material is suitable as a dopant for a semiconductor material depends on the atomic properties of both. In general, dopants are classified as donors and acceptors according to the positive or negative charge they bring to the doped material. The valence electrons brought by the donor atoms are mostly covalent bonds with the doped material atoms, and thus are bound. Electrons that do not form covalent bonds with the doped material atoms are weakly bound by the donor atom, which is also called the donor electron.

Compared with the valence electrons of intrinsic semiconductors, the energy required for the donor electrons to transition to the conduction band is lower, and it is easier to move in the lattice of the semiconductor material to generate current. Although the donor electron gains energy and jumps to the conduction band, it does not leave a hole like the intrinsic semiconductor, and the donor atom will only be fixed in the lattice of the semiconductor material after losing its electrons. Therefore, this kind of semiconductor that obtains excess electrons to provide conduction due to doping is called N-type semiconductor (N-type semiconductor), where n stands for negatively charged electrons.

In contrast to the donor, after the acceptor atom enters the semiconductor lattice, because the number of valence electrons is less than the number of valence electrons of the semiconductor atom, it will equivalent to bring a vacancy, and this extra vacancy can be regarded as an electric hole. The doped semiconductor is called a P-type semiconductor, where p stands for positively charged hole.

The effect of doping is illustrated by an intrinsic semiconductor of silicon. Silicon has four valence electrons, and dopants commonly used in silicon include trivalent and pentavalent elements. When a trivalent element such as boron, which has only three valence electrons, is doped into a silicon semiconductor, boron plays the role of acceptor, and a silicon semiconductor doped with boron is a P-type semiconductor. Conversely, if a pentavalent element such as phosphorus is doped into a silicon semiconductor, phosphorus plays the role of donor, and the doped phosphorus silicon semiconductor becomes an N-type semiconductor.

A semiconductor material may be doped with donor and acceptor, and how to decide whether the semiconductor is N-type or P-type must depend on the doped semiconductor, the acceptor brings a higher concentration of holes or the donor brings a higher concentration of electrons, that is, which is the "majority carrier" of the semiconductor. The opposite of a majority carrier is a minority carrier. For the analysis of the operating principle of semiconductor components, the behavior of a small number of carriers in the semiconductor has a very important position, in line with the diode.