Influence of⁶⁰Co gamma radiation on fluorine plasma treated enhancement-mode high-electron-mobility transistor

Abstract

AlGaN/GaN depletion-mode high-electron-mobility transistor (D-HEMT) and fluorine (F) plasma treated enhancement-mode high-electron-mobility transistor (E-HEMT) are exposed to 60 Co gamma radiation with a dose of 1.6 Mrad (Si). No degradation is observed in the performance of D-HEMT. However, the maximum transconductance of E-HEMT is increased after radiation. The 2DEG density and the mobility are calculated from the results of capacitance-voltage measurement. The electron mobility decreases after fluorine plasma treatment and recovers after radiation. Conductance measurements in a frequency range from 10 kHz to 1 MHz are used to characterize the trapping effects in the devices. A new type of trap is observed in the F plasma treated E-HEMT compared with the D-HEMT, but the density of the trap decreases by radiation. Fitting of Gp/ω data yields the trap densities D T = (1 − 3) × 10 12 cm −2 • eV −1 and D T = (0.2 − 0.8) × 10 12 cm −2 •eV −1 before and after radiation, respectively. The time constant is 0.5 ms-6 ms. With F plasma treatment, the trap is introduced by etch damage and degrades the electronic mobility. After 60 Co gamma radiation, the etch damage decreases and the electron mobility is improved. The gamma radiation can recover the etch damage caused by F plasma treatment.

The effects of60Co γ-ray irradiation on the DC characteristics of enhancement-mode AlGaN/GaN high-electron-mobility transistors

“…[6−11] However, there has been little research on the radiation reliability [12] of fluorine plasma treatment Emode AlGaN/GaN HEMTs and the methods to improve its radiation hardness. [13] In the present paper, we realize normally-off Al-GaN/GaN HEMT devices by using fluoride-based plasma treatment. An E-mode AlGaN/GaN HEMT is exposed to 60 Co γ-rays at a dose of 3 Mrad (Si).…”