In/sub 0.52/Al/sub 0.48/As/In/sub x/Ga/sub 1-x/As (0.53>or=x>or=0.70) lattice-matched and strained heterostructure insulated-gate FETs

摘要

The DC and microwave properties of In/sub 0.52/Al/sub 0.48/Al/In/sub x/Ga/sub 1-x/As (0.53>or=x>or=0.70) heterostructure insulated gate field-effect transistors (HIGFETs) with a quantum well channel design are presented. DC and microwave transconductances (g/sub m/) are enhanced as the In content is increased in the InGaAs channel. An intrinsic microwave g/sub m/ value of 428 mS/mm and a K-factor of 1140 mS/mm-V have been obtained for 1.0- mu m gate length with the 65% In channel devices. The sheet charge density, drift mobility, transconductance, current-gain cutoff frequency (f/sub T/), and maximum oscillation frequency (f/sub max/) all show a continuous improvement up to 65% In content (f/sub T/=22.5 GHz with 53% and f/sub T/=27 GHz with 65% In; the corresponding f/sub max/ change is from 6.5 to 8 GHz). The device performance degrades as the In content is increased to 70%. DC and microwave characteristics show the presence of negative differential resistance (NDR) up to 2.7 GHz.