Mechanical tensile strain for AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors on a silicon-on-insulator substrate

Abstract

The impacts of various tensile strains on both DC and RF performance of AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) on a silicon-on-insulator (SOI) substrate were investigated using pulsed-IV and pulsed-S-parameter tests. The sensitivity of MIS-HEMTs to various tensile strains was observed via pulse measurements because of the improved self-heating effect. The DC and RF performance of MIS-HEMTs on a SOI substrate were found to be enhanced with the pulse width decreasing under small tensile strain. A significant hot phonon effect was observed for MIS-HEMTs under larger tensile strain, particularly for shorter pulse widths. Additionally, an obvious reduction of fmax was observed under larger tensile strain because the channel resistance increased via the hot phonon effect, despite the increase in ft. The results indicated that tensile strain in the ultra-thin thinned substrate of AlGaN/GaN HEMTs should be carefully monitored in compact packages for high-power and high-frequency applications.