High-Fluence Proton-Induced Degradation on AlGaN/GaN High-Electron-Mobility Transistors

The electrical characteristics and low-frequency noise (LFN) of AlGaN/GaN high-electron-mobility transistors (HEMTs) after 3-MeV proton irradiation up to a total dose of 5.0 × 10
¹⁴
p/cm
²
have been studied in this article. The devices experienced a 14.6% decrease in the saturation current, a 0.35-V positive shift in the threshold voltage (Vth), and a significant decrease in the reverse gate leakage current after 3-MeV proton irradiation. Extracted by the LFN method, the flatband voltage noise power spectral density (SVfb) increases from 4.112 × 10
^-12
· Hz
^-1
to 5.603 × 10
^-12
· Hz
^-1
, and the trap density increases from 2.79 × 10
¹⁷
to 3.84 × 10
¹⁷
cm
^-3
· eV
^-1
after the radiation. The main degradation mechanism is considered to be the increase of negatively charged trap density in the channel, which depletes more electrons and reduces the carrier mobility in the channel 2-D electron gas (2DEG). We also extracted the radiation-induced trapped charge density according to the theoretical calculation; the result is consistent with the LFN measurement.