ABSTRACT
The semiconducting material which serves as substrate for integrated circuits (IC) is mostly silicon single crystal and is supplied to IC manufacturers in the form of thin wafers. This chapter describes the features of transmission and reflection spectra of Si wafer. Si doped with boron has positive holes and is called a p-type semiconductor, while Si doped with phosphorus has a free electron and is called an n-type semiconductor. The measurement of impurities is important in the IC industry to characterize the material. Galium arsenside is also an important material in the semiconductor industry and is supplied as wafer also. The relationship between superconduction and crystal structure is discussed here based on the infrared (IR) study of an organic superconducting material. As the concentration of dopant increases, the electrical conductivity increases due to free holes or electrons. These holes and electrons allow electric conduction. As their concentration increases the transmission of IR radiation decreases.
