Schottky and ohmic contacts to SiC

This chapter covers Schottky (rectifying barrier) and ohmic (nonrectifying, no barrier) contacts to SiC. There are a few devices such as the MESFET and the Schottky diode that actually need Schottky contacts. However, for most devices ohmic contacts are preferred between a metal and semiconductor. To understand the formation of ohmic contacts, the theory for Schottky contacts is needed, and it is therefore covered first in this chapter. The formation methods are similar for both contact types, and are covered mainly in the section on Schottky contacts. The only way to know if a contact is good enough is to measure its electrical characteristics, and therefore electrical characterisation methods are covered in detail for both contact types.