26 CHAPTER 1. STRUCTURAL PROPERTIES OF SEMICONDUCTORS
IMPORTANT SUBSTRATES Statue / ISSUES
- Silicon (Si) Mature, 12-inch diameter. Next generation
15-inch diameter.
- Gallium Arsenide (GaAs) Mature, 6-inch diameter.
- Indium Phosphide (InP) Mature, brittle, maximum diameter 4 inches.
- Silicon Carbide (SiC) Developing technology, 3-inch diameter in
production. Micropipe density 1 cm-2 for
n-type and 100 cm-2 for semi-insulating.
- Germanium (Ge) 6-inch diameter. Limited supply. Water-
soluble oxide.
- Sapphire (Al 2 O 3 ) Hydrothermal growth. 4-inch diameter
available. Low thermal conductivity.
- Aluminum Nitride (AlN) 1-inch diameter. Early stages of
development, sublimation growth technique.
- Gallium Nitride (GaN)
- Indium Antimonide (InSb)
- Zinc Oxide (ZnO)
2-inch diameter substrates by HVPE.
Dislocation density 10^6 cm-2.
2-inch diameter, early stages of
development.
Hydrothermal growth. 2-inch diameter
available. Dislocation density < 100 cm-2 for
n-type.
Table 1.3: A brief overview of important substrates available in semiconductor technology.
Problem 1.5Assume that a Ga-As bond in GaAs has a bond energy of 1.0 eV. Calculate
the energy needed to cleave GaAs in the (001) and (110) planes.
Problem 1.6Consider a hcp structure shown in the text. Prove the relation given by
c/a=
√
8 /3=1. 633.
Problem 1.7Why are entropy considerations unimportant in dislocation generation?
Problem 1.8A coherently strained quantum well laser has to made from InxGa 1 −xAs on
a GaAs substrate. If the minimum thickness of the region is 50A, calculate the maximum ̊
