DRIFT-MOBILITY PROFILES IN GAAS FIELD-EFF ECT TRANSISTORS

A new method for evaluating drift mobility profiles in field effect tr ansistors is proposed. The frequency dependent Schottky gate admittanc e and the low-field transconductance is used to calculate mobility dat a. The frequency dependent admittance leads to gate capacitances that are free from series resistance, minority carrier and deep level effec ts. The method provides a convenient tool for routine on-wafer measure ments of LSI circuit transport properties. As an example, drift mobili ty profiles in long, short, wide and narrow channel LDD- and BPLDD-GaA s-MESFET with various p-buffer layer concentration levels are discusse d. Such devices are the standard device for digital GaAs integrated ci rcuits with LSI complexity.