Reliability Studies on AlGaN/GaN Metal-Insulator-Semiconductor High-Electron-Mobility Transistors with Through-Substrate via Technique and Backside Heat Sink Metal on Silicon-on-Insulator Substrates

AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) on silicon-on-insulator (SOI) substrates using the through-substrate via (TSV) and back side metal techniques are studies for improving thermal dissipation and device performances. The measured VTH values of the standard (SOI w/o TSV) and MIS-HEMT with TSV (SOI-TSV) devices are −4.1 and −3.9 V. The drain ON/OFF current ratio (ION/IOFF) values of SOI w/o TSV and SOI-TSV devices are 12.96 and 61.62 and the subthreshold swing of these two structures are 248 and 226 mV/dec. The results show that the reduced vertical leakage current in SOI-TSV device exhibited better ION/IOFF ratio and the subthreshold swing than the SOI w/o TSV device. In gate-to-drain current-voltage characteristics, the SOI-TSV devices shows a lower leakage current under the VGS from 0 to −10 V operation than the standard device. Additionally, the reliability and the trapping phenomenon of these two devices were studied using low-frequency noise and pulse measurements. Based on these two structures were processed on the same wafer, the better heat dissipation of SOI-TSV device with Ti/Al back side layer decreases the generation of hot carriers at the reliability stress measurement.