Fundamentals of Silicon Carbide Technology: Growth, Characterization, Devices and Applications

6.4 Metallization

Schottky contacts are the key component of Schottky barrier diodes (SBDs) and metal-semiconductor field effect transistors (MESFETs). The basic theory and knowledge of Schottky contacts are also important in understanding ohmic contacts. Formation of ohmic contacts is essential in any semiconductor devices. Both types of contacts are required for a variety of electrical characterization techniques of materials, including , DLTS, and Hall effect measurements. Several review papers on Schottky contacts [319–321] and ohmic contacts [320, 322–327] on SiC have been published.

6.4.1 Schottky Contacts on n-Type and p-Type SiC

6.4.1.1 Fundamentals

In the case of SiC, most metals deposited on SiC work as Schottky contacts, as long as the SiC material is not heavily doped and high-temperature contact sintering is not performed. When a metal and a semiconductor are brought into contact, the Fermi levels of the two materials line up at equilibrium (zero bias). The energy band diagrams of a Schottky barrier on (a) n-type and (b) p-type semiconductor at zero bias are shown in Figure 6.69. Here, is the barrier height, the built-in potential, and (or ) the position of the Fermi ...