Correlation of undoped, in-alloyed, and whole-ingot annealed semi-insulating GaAs substrates for low-noise microwave amplifiers

The quality of 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 whale-ingot annealed semi-insulating substrates. We investigated differences in Si implant activation, electrical profiles, and uniformity of material, device, and circuit parameters. The best noise figure of 1.33 dB at 10 GHz was measured on a 0.5-µm low-noise FET fabricated on a 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.