Chapter 5 GaAs LSI Fabrication and Performance

Abstract

Publisher Summary In this chapter, technologies leading to the present state of gallium arsenide (GaAs) digital large-scale integration (LSI) are discussed, mainly focusing on materials, fabrication processes and LSI performance. GaAs LSI development can be divided into four generations, according to characteristic technologies developed. The first generation is from 1974 to 1977. GaAs metal-semiconductor field effect transistor (MESFET) integrated circuits IC complexity increased from the elementary stage of logic gates to small-scale integration (SSIs) and medium-scale integration (MSIs). Circuits were realized using epitaxial layers with mesa device isolation. The next generation is from 1978 to 1980. The fabrication process was greatly improved using selective ion implantation in a semi-insulating substrate. The planar and uniform process developments resulted in MSIs and the first GaAs LSIs. The third generation (1980–1984) is referred to as the LSI generation. Direct coupled FET logic (DCFL) with low power dissipation was used, and several kinds of LSI-directed self-aligned FET structures were developed. The fourth generation started in 1985 with the attainment of GaAs IC commercial production and has been continued along with research and development of submicron gate and very-large-scale integration (VLSI) technologies.