Electrothermal Characteristics of Delta-Doped β-Ga2O3 Metal-Semiconductor Field-Effect Transistors

A 2-D electrothermal model of delta-doped b eta-gallium oxide ( $\beta $ -Ga2O3) metal-semiconductor field-effect transistor (MESFET) is developed by using TCAD Sentaurus to investigate its electrical and thermal characteristics. The temperature and electric field-dependent electron mobility model is incorporated to predict I-V characteristics of the FET, which are in good agreement with the measured I-V characteristics. We investigated the effect of bias voltages on an electric field, a current path, a volumetric heat generation profile, and a peak temperature at a given total heat dissipation. The peak temperature is observed to be significantly different at the same power dissipation but different bias conditions, e.g., the peak temperature is x007E;9 K higher when the drain-to-source voltage (V-ds) x003D; 25 V and the gate-to-source voltage (V-gs) x003D; -6 V compared with V-ds x003D; 8.3 V and V-gs x003D; 2 V at the total power dissipation of 1.16 W/mm. This difference is attributed to the change in the electron Joule heating profile with the applied bias voltage. The effects of the location of the delta-doping layer, the gate-drain spacing, and the source-drain spacing are investigated to guide a future device fabrication. The variation in these parameters mainly affects electrical characteristics such as ON-resistance, saturation current, threshold voltage, and so on. The thermal characteristics, such as peak temperature, temperature profile, and so on, are not significantly affected at a low-power dissipation.