Low-Noise Microwave Performance of 30 nm GaInAs MOS-HEMTs: Comparison to Low-Noise HEMTs

Abstract

GaInAs-based Metal Oxide Semiconductor High Electron Mobility Transistors (MOS-HEMTs) can in principle combine the wide bandwidth of HEMTs to the low gate leakage current of MOSFETs in a single deeply-scaled ultrahigh speed low-noise technology. Despite advances in the fabrication of MOS-HEMT devices and MMICs, the transistor microwave noise properties of GaInAs MOS-HEMT devices have not yet been reported. In the present study, the room temperature DC and wideband RF noise properties (8-50 GHz) of GaInAs channel MOS-HEMTs are characterized and contrasted to those of a 50 nm low-noise HEMT with the same channel composition/thickness and similar ${f}_{{\text {T}}}$ : at a given bias ${V}_{{\text {DS}}} = {0.5}$ V, the HEMT provides lower minimal noise figures ( ${\textit {NF}}_{{\text {MIN}}}$ ) and higher associated gain. In contrast to HEMTs, the MOS-HEMTs particularly suffer from lower frequency noise contributions attributed to enhanced impact ionization. Remarkably, operation at ${V}_{{\text {DS}}} = {0.4}$ V to mitigate ionization enables MOS-HEMTs to match the HEMT wideband ${\textit {NF}}_{{\text {MIN}}}$ performance despite a significantly poorer low-field channel mobility. The present MOS-HEMTs show the highest reported maximum oscillation frequency ${f}_{{\text {MAX}}} = 637$ GHz for a measured gate length ${L}_{G} = {33}$ nm and a ( $2\times15$ ) $\mu \text{m}$ width. Gate annealing is shown to be deleterious to the MOS-HEMT DC and noise properties.