ABSTRACT
In high-speed electronic device applications GaAs and its related compounds are superior to silicon due to their higher carrier mobilities which enhance device speed and current handling capability. Molecular beam epitaxy (MBE) and metallorganic chemical vapour deposition (MOCVD) have been the most important growth techniques in the production of high-quality epilayers for device fabrication. An important problem with MBE is the difficulty in controlling the phosphorus vapour pressure during MBE growth. Therefore phosphorus-based materials are not easy to grow with this technique. Another problem is the low throughput of MBE growth. MOCVD, with its batch capability, is more suitable for volume manufacturing. This chapter will concentrate on the growth, fabrication and characteristics of MOCVD-grown, GaAs-based heterostructure field effect and bipolar transistors which have been the most important devices in digital and microwave applications. It is assumed that the reader is familiar with the basic principles involving the operation of homojunction field effect and bipolar transistors at the level of an undergraduate course on solid-state devices.
