Fabrication and characterization of InGaAs/InAlAs insulated gate pseudomorphic HEMTs having a silicon interface control layer

A novel InGaAs/InAlAs insulated gate (IG) pseudomorphic high electron mobil ity transistor (PHEMT) having a silicon interface control layer (Si ICL) is successfully fabricated and characterized. Systematic efforts to character ize and optimize the insulated gate structure and the PHEMT fabrication pro cess were made by using in-situ X-ray photoelectron spectroscopy (XPS) and capacitance-voltage (C-V) techniques. This led to successful fabrication of a novel IG-PHEMT showing excellent stable DC characteristics with a good p inch off and a high transconductance (177 mS/mm), very small gate leakage c urrents, very high gate breakdown voltages (about 40 V) and respectable RF characteristics f(T) = 9 GHz and f(max) = 38 GHz.