ABSTRACT
This chapter reviews metal semiconductor field effect transistors (MESFETs) operation, degradation of gallium arsenide (GaAs) MESFET performance at high temperatures, GaAs reliability, contact metallization, and work done with other III-V compounds to demonstrate operation at temperatures up to 550°C. High-temperature operation of bipolar transistors is limited by reverse leakage current in the base-collector junction. This reverse current can be reduced in a heterojunction bipolar transistor (HBT) using a wide bandgap semiconductor in the collector. In an as-deposited contact, the semiconductor is doped by some means, such as ion-implantation (and annealing) or during its epitaxial growth. While vapor-phase epitaxial (VPE) growth is currently the most practical means of silicon carbide (SiC) active layer formation, SiC materials technology, including active layer formation, is still immature. The development of SiC boule growth has established the potential for obtaining SiC crystals and wafers suitable for microelectronic device fabrication.
