Future devices for GaAs

The question of future devices in GaAs must be influenced by the background of possible slowed growth, and must consider some of the technical issues affecting the cost of GaAs products, particularly integrated circuits. Following a brief review of some fundamental limits imposed by the GaAs material itself, the high electron mobility transistor (HEMT), heterojunction bipolar transistor (HBT), hot-electron transistor (HET) and the permeable base transistor (PBT) are discussed, and commented upon for their suitability as the basis of GaAs integrated circuits. Finally, the dependence of chip yield and manufacturability upon the resolution of physics- and technology-related issues is illustrated with reference to a chip case study