InP-based heterostructure field-effect transistors with high-quality short-period (InAs) 3 m/(GaAs) 1 m superlattice channel layers

Abstract

InP-based heterostructure field-effect transistors (HFETs) incorporating an (InAs) 3 m /(GaAs) 1 m short-period superlattice (SPSL) subchannel are compared to HFETs using a ternary In 0.77Ga 0.23As alloy with respect to transport and device performance. Room temperature Hall mobility of 13100 cm 2/ V · s was measured on a (InAs) 3/(GaAs) 1 SPSL with a two-dimensional electron sheet density of 3.1 × 10 12 cm −2, which are the highest mobilities in such a material system so far. Sheet resistances as low as 35 Ω □ at 17 K confirm the high quality of the (InAs) 3/(GaAs) 1 SPSL channel material resulting in high transit and unilateral gain cut-off frequencies of 63 and 190 GHz, respectively, in HFETs exhibiting gate lengths of 0.65 μm. Nevertheless, a significant improvement compared to the ternary alloy could not be verified.