Impact of Temperature and Interface Traps on Threshold Voltage and Carrier Mobility of Hydrogen-Terminated Diamond...

We present a Sentaurus TCAD model calibrated for the hydrogen-terminated diamond p-channel MOSFET reported by Hirama et al. and validated using the published transfer characteristics. We used the calibrated model to analyze threshold voltage (V_th) and effective mobility (μ_eff) over a temperature range from 300 to 600 K and an interface-trap density range from 10¹² to 10¹⁶ cm^-2·eV^-1. The analysis shows three main trends: (i) a drain-bias-dependent shift in V_th that becomes stronger at higher temperatures; (ii) a threshold shift toward more negative values with increasing temperature and interface-trap density, showing a coupled thermal trap effect; and (iii) a mobility response that stays near the phonon-limited regime at low trap densities but degrades rapidly as trap density increases. We extracted compact empirical expressions for ΔV_th (T, D_it) and μ_eff (T, D_it) that reproduce the simulated trends with good accuracy for device-level comparison. The results show that interface-trap control is important to achieve thermally stable, high-performance diamond MOSFETs.