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

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 f_max was observed under larger tensile strain because the channel resistance increased via the hot phonon effect, despite the increase in f_t. 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.