Gate length scaling in high performance InGaP/InGaAs/GaAs PHEMT's

The performance of InGaP-based pHEMT's as a function of gate length has bee n examined experimentally. The direct-current and microwave performance of pHEMT's with gate lengths ranging from 1.0-0.2 mu m has been evaluated. Ext rinsic transconductances from 341 mS/mm for 1.0 mu m gate lengths to 456 mS /mm for 0.5 mu m gate Lengths were obtained. High-speed device operation ha s been verified, with f(t) of 93 GHz and f(max) of 130 GHz for 0.2 mu m gat e lengths, The dependence of de and small-signal device parameters on gate Length has been examined, and scaling effects in InGaP-based pHEMT's are ex amined and compared to those for AlGaAs/InGaAs/GaAs pHEMT's, High-field tra nsport in InGaP/InGaAs heterostructures is found to he similar to that of A lGaAs/InGaAs heterostructures, The lower epsilon(r) Of InGaP relative to Al GaAs is shown to be responsible for the early onset of short-channel effect s in InGaP-based devices.