High-Temperature Characterization of AlGaN Channel High Electron Mobility Transistor Based on Silicon Substrate

In this paper, it is demonstrated that the AlGaN high electron mobility transistor (HEMT) based on silicon wafer exhibits excellent high-temperature performance. First, the output characteristics show that the ratio of on-resistance (R_ON) only reaches 1.55 when the working temperature increases from 25 °C to 150 °C. This increase in R_ON is caused by a reduction in optical phonon scattering-limited mobility (μ_OP) in the AlGaN material. Moreover, the device also displays great high-performance stability in that the variation of the threshold voltage (ΔV_TH) is only 0.1 V, and the off-state leakage current (I_D,off-state) is simply increased from 2.87 × 10^-5 to 1.85 × 10^-4 mA/mm, under the operating temperature variation from 25 °C to 200 °C. It is found that the two trap states are induced at high temperatures, and the trap state densities (D) of 4.09 × 10¹²~5.95 × 10¹² and 7.58 × 10¹²~1.53 × 10¹³ cm^-2 eV^-1 are located at E_T in a range of 0.46~0.48 eV and 0.57~0.61 eV, respectively, which lead to the slight performance degeneration of AlGaN HEMT. Therefore, this work provides experimental and theoretical evidence of AlGaN HEMT for high-temperature applications, pushing the development of ultra-wide gap semiconductors greatly.