WHOLE-INGOT ANNEALED SEMI-INSULATING GaAs SUBSTRATES FOR LOW-NOISE MICROWAVE AMPLIFIERS.

The quality of liquid-encapsulated Czochralski (LEC) grown GaAs substrates critically affects the final low-noise microwave device and circuit performance as evidenced by comparing Si-implanted undoped, In-alloyed, and whole-ingot annealed semi-insulating substrates. Differences in Si-implant activation, electrical profiles, and uniformity of material, device, and circuit parameters were examined. The best noise figure of 1. 33 dB at 10 GHz was measured on a 0. 5- mu m low-noise FET fabricated on the high-pressure whole-ingot annealed LEC wafer. A noise figure of 2. 0 dB with associated gain of 24 dB at 10 GHz was achieved for a monolithic two-stage low-noise amplifier fabricated on the standard high-pressure LEC substrate.