Molecular beam epitaxy regrowth and device performance of GaAs-based pseudomorphic high electron mobility transistors using a thin indium passivation layer

Abstract

Using the technique of molecular beam epitaxy, an indium passivation layer as thin as several tens of Angstrom was implemented to protect underlying III-V epilayers from carbon and oxygen contamination. After the subsequent desorption of the passivation layer, GaAs-based pseudomorphic high electron mobility transistors (PHEMTs) were regrown. Negligible residual carriers were detected at the interface between the regrown PHEMTs and the underlying layer, resulting in a superior performance. The regrown PHEMTs with a 1 x 100 mum(2) gate demonstrated an extrinsic transconductance g(me) as high as 330 mS mm(-) (1). Microwave measurements showed that the current gain cut-off frequency f(t) was 26.5 GHz and the maximum oscillation frequency f(max) was up to 48 GHz. A small-signal equivalent circuit model of the regrown PHEMTs was also evaluated. (C) 2000 Kluwer Academic Publishers.