InAlAs/InGaAs Pseudomorphic High Eelectron Mobility Transistors Grown by Molecular Beam Epitaxy on the InP Substrate

Abstract

A novel PMMA/PMGI/ZEP520 trilayer resist electron beam lithograph (EBL) technology is successfully developed and used to fabricate the 150 nm gate-length In0.7Ga0.3As/In0.52Al0.48As Pseudomorphic HEMT on an InP substrate, of which the material structure is successfully designed and optimized. A perfect profile of T-gate is successfully obtained. These fabricated devices demonstrate excellent dc and rf characteristics: the transconductance Gm, maximum saturation drain-to-source current IDSS, threshold voltage VT, maximum current gain frequency fT derived from h21, maximum frequency of oscillation derived from maximum available power gain/maximum stable gain and from unilateral power-gain of metamorphic InGaAs/InAlAs high electron mobility transistors (HEMTs) are 470 mS/mm, 560 mA/mm, −1.0 V, 76 GHz, 135 GHz and 436 GHz, respectively. The excellent high frequency performances promise the possibility of metamorphic HEMTs for millimeter-wave applications.