The Diamond Structure
As already stated, silicon is the most common semiconductor material. Silicon is referred
to as a group IV element and has a diamond crystal structure. Germanium is
also a group IV element and has the same diamond structure. A unit cell of the. diamond
structure, shown in Figure 1.10, is more complicated than the simple cubic
structures that we have considered up to this point.
We may begin to understand the diamond lattice by considering the tetrahedral
structure shown in Figure I . 1 I. This structure is basically a body-centered cubic with
four of the comer atoms missing. Every atom in the tetrahedral structure has four
nearest neighbors and it is this structure which is the basic building block of the diamond
lattice.
There are several ways to visualize the diamond structure. One way to gain a further
understanding of the diamond lattice is by considering Figure l. 12. Figure l. 12a
shows two body-centered cubic, or tetrahedral, structures diagonally adjacent to each
other. The shaded circles represent atoms in the lattice that are generated when the
structure is translated to the right or left, one lattice constant, a. Figure 1.12b represents
the top half of the diamond structure. The top half again consists of two tetrahedral
structures joined diagonally, but which are at 90" with respect to the bottom half
diagonal. An important characteristic of the diamond lattice is that any atom
within the diamond structure will have four nearest neighboring atoms. We will note
this characteristic again in our discussion of atomic bonding in the next section.
The diamond structure refers to the particular lattice in which all atoms are of the
same species, such as silicon or germanium. The rincblende (sphalerite) structure
differs from the diamond structure only in that there are two different types of atoms
in the lattice. Compound semiconductors, such as gallium arsenide, have the zincblende
structure shown in Figure 1.13. The important feature of both the diamond
and the zincblende structures is that the atoms are joined together to form a tetrahedron.
Figure 1.14 shows the basic tetrahedral structure of GaAs in which each Ga
atom has four nearest As neighbors and each As atom has four nearest Ga neighbors.
This figure also begins to show the interpenetration of two sublattices that can be used
to generate the diamond or zincblende lattice.
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to as a group IV element and has a diamond crystal structure. Germanium is
also a group IV element and has the same diamond structure. A unit cell of the. diamond
structure, shown in Figure 1.10, is more complicated than the simple cubic
structures that we have considered up to this point.
We may begin to understand the diamond lattice by considering the tetrahedral
structure shown in Figure I . 1 I. This structure is basically a body-centered cubic with
four of the comer atoms missing. Every atom in the tetrahedral structure has four
nearest neighbors and it is this structure which is the basic building block of the diamond
lattice.
There are several ways to visualize the diamond structure. One way to gain a further
understanding of the diamond lattice is by considering Figure l. 12. Figure l. 12a
shows two body-centered cubic, or tetrahedral, structures diagonally adjacent to each
other. The shaded circles represent atoms in the lattice that are generated when the
structure is translated to the right or left, one lattice constant, a. Figure 1.12b represents
the top half of the diamond structure. The top half again consists of two tetrahedral
structures joined diagonally, but which are at 90" with respect to the bottom half
diagonal. An important characteristic of the diamond lattice is that any atom
within the diamond structure will have four nearest neighboring atoms. We will note
this characteristic again in our discussion of atomic bonding in the next section.
The diamond structure refers to the particular lattice in which all atoms are of the
same species, such as silicon or germanium. The rincblende (sphalerite) structure
differs from the diamond structure only in that there are two different types of atoms
in the lattice. Compound semiconductors, such as gallium arsenide, have the zincblende
structure shown in Figure 1.13. The important feature of both the diamond
and the zincblende structures is that the atoms are joined together to form a tetrahedron.
Figure 1.14 shows the basic tetrahedral structure of GaAs in which each Ga
atom has four nearest As neighbors and each As atom has four nearest Ga neighbors.
This figure also begins to show the interpenetration of two sublattices that can be used
to generate the diamond or zincblende lattice.
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