New Ga(0.47)In(0.53)As field effect transistor with a lattice- mismatched GaAs gate for high-speed circuits.

A Ga(0.47)In(0.53)As field effect transistor with a novel GaAs lattice-mismatched gate (called LMG-FET for short) is reported. The device shows an extrinsic dc transconductance of 108 mS/mm for 1.4icron gate length and 240micron width. Despite a 3. 7% lattice mismatch between GaAs and Ga(0.47)In(0.53)As, the LMG-FET shows stable operation even at 80C (with a 13% increase in transconductances), exhibits negligible current drift, and suffers very little change in threshold voltages (0.05 V) under illumination. This technology may find applications in high-speed lightwave transmission as well as high-speed digital circuits.