Investigation of impact ionization and flicker noise properties in indium aluminum arsenide/indium gallinum arsenide metamorphic high electron mobility transistors with various work function-gate metals

This study investigates the effect of impact ionization using Ir, Pt, Pd, Ti gate metals and the direct correlation between these high work function metals and low frequency noise (LFN) on an In0.4Al0.6As/In0.4Ga0.6As metamorphic high electron mobility transistor (MHEMT). The effect of impact ionization on DC, RF, and cryogenic LFN is systematically studied and discussed. Gate metals with high work functions are used to suppress the kink effect and gate leakage current. Experimental results suggest that the Ir gate MHEMT exhibits superior thermal stable properties in a strong electrical field at various temperatures, associated with high gain, high current, and excellent low-frequency noise performance.