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

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(T): at a given bias V-DS = 0.5 V, the HEMT provides lower minimal noise figures (NFMIN) 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-DS = 0.4 V to mitigate ionization enables MOS-HEMTs to match the HEMT wideband NFMIN performance despite a significantly poorer low-field channel mobility. The present MOS-HEMTs show the highest reported maximum oscillation frequency f(MAX) = 637 GHz for a measured gate length L-G = 33 nm and a (2 x 15) mu m width. Gate annealing is shown to be deleterious to the MOS-HEMT DC and noise properties.