Title :
Current Collapse Reduction in AlGaN/GaN HEMTs by High-Pressure Water Vapor Annealing
Author :
Asubar, Joel T. ; Kobayashi, Yohei ; Yoshitsugu, Koji ; Yatabe, Zenji ; Tokuda, Hirokuni ; Horita, Masahiro ; Uraoka, Yukiharu ; Hashizume, Tamotsu ; Kuzuhara, Masaaki
Author_Institution :
Dept. of Electr. Eng., Univ. of Fukui, Fukui, Japan
Abstract :
We have demonstrated for the first time a remarkable reduction of current collapse in AlGaN/GaN high-electron-mobility transistors (HEMTs) by high-pressure water vapor annealing (HPWVA). The device subjected to HPWVA exhibited considerably low dynamic ON-resistance (RON), suggesting highly improved performance of these devices. Analyses of the results on normalized dynamic RON experiments have shown the elimination of deeper traps by HPWVA, leading to the substantially reduced current collapse. X-ray photoelectron spectroscopy (XPS) studies revealed a significant increase in the oxygen core-level O 1s peak. Moreover, angle-resolved XPS suggested the formation of surface oxide layer. These results indicate that the effective reduction of current collapse in the HPWVA-processed samples is likely due to the incorporation of active oxygen species generated by the HPWV into the AlGaN surface. These oxygen atoms eventually fill up near-surface nitrogen vacancies and promote the formation of Ga2O3 native oxide and possibly Ga2O suboxide, which is known to be an excellent III-V surface passivant. HPWVA is a relatively simple, low-damage, and low-temperature process, and hence, it is found to be a highly feasible and promising alternative for realizing AlGaN/GaN HEMTs with improved performance.
Keywords :
III-V semiconductors; X-ray photoelectron spectra; aluminium compounds; annealing; gallium compounds; high electron mobility transistors; passivation; wide band gap semiconductors; AlGaN-GaN; Ga2O3; HEMT; X-ray photoelectron spectroscopy; XPS; active oxygen; current collapse reduction; high electron mobility transistor; high pressure water vapor annealing; low dynamic on-resistance; native oxide formation; near surface nitrogen vacancies; surface passivantion; Aluminum gallium nitride; Annealing; Gallium nitride; HEMTs; Logic gates; MODFETs; Wide band gap semiconductors; AlGaN/GaN high-electron-mobility transistor (HEMT); ON-resistance; X-ray photoelectron spectroscopy (XPS); X-ray photoelectron spectroscopy (XPS).; current collapse; high-pressure water vapor annealing (HPWVA); normalized dynamic ${R}_{mathrm{scriptscriptstyle ON}}$ (NDR); normalized dynamic RON (NDR);
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2015.2440442