The Crystal Structure of Solids: SEMICONDUCTOR MATERIALS
Semiconductors are a group of materials having conductivities between those of metals
and insulators. Two general classifications of semiconductors are the elemental
semiconductor materials, found in group IV of the periodic table, and the compound
semiconductor materials, most of which are formed from special combinations of
group I11 and group V elements. Table 1.1 shows a portion of the periodic table in
which the more common semiconductors are found and Table 1.2 lists a few of the
semiconductor materials. (Semiconductors can also be formed from combinations of
group I1 and group VI elements. but in general these will not beconsidered in this text.)
The elemental materials, those that are composed of single species of atoms, are
silicon and germanium. Silicon is by far the most common semiconductor used in integrated
circuits and will be emphasized to a great extent.
The two-element, or binary compounds such as gallium arsenide or gallium phosphide
are formed by combining one group 111 and one group V element. Gallium
arsenide is one of the more common of the compound semiconductors. Its good optical
properties make it useful in optical devices. GaAs is also used in specialized applications
in which, for example, high speed is required.
We can also form a three-element, or ternor3 compound semiconductor. An example
is A1,Gal-,As, in which the subscript x indicates the fraction of the lower
atomic number element component. More complex semiconductors can also be
formed that provide flexibility when choosing material properties.
|
and insulators. Two general classifications of semiconductors are the elemental
semiconductor materials, found in group IV of the periodic table, and the compound
semiconductor materials, most of which are formed from special combinations of
group I11 and group V elements. Table 1.1 shows a portion of the periodic table in
which the more common semiconductors are found and Table 1.2 lists a few of the
semiconductor materials. (Semiconductors can also be formed from combinations of
group I1 and group VI elements. but in general these will not beconsidered in this text.)
The elemental materials, those that are composed of single species of atoms, are
silicon and germanium. Silicon is by far the most common semiconductor used in integrated
circuits and will be emphasized to a great extent.
The two-element, or binary compounds such as gallium arsenide or gallium phosphide
are formed by combining one group 111 and one group V element. Gallium
arsenide is one of the more common of the compound semiconductors. Its good optical
properties make it useful in optical devices. GaAs is also used in specialized applications
in which, for example, high speed is required.
We can also form a three-element, or ternor3 compound semiconductor. An example
is A1,Gal-,As, in which the subscript x indicates the fraction of the lower
atomic number element component. More complex semiconductors can also be
formed that provide flexibility when choosing material properties.
|
Post a Comment