Electrothermal Characteristics of Delta-Doped $\beta$ -Ga2O3 Metal–Semiconductor Field-Effect Transistors

A 2-D electrothermal model of delta-doped b eta-gallium oxide (
$\beta $
-Ga
₂
O
₃
) 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 ~9 K higher when the drain-to-source voltage (
V
_ds
) = 25 V and the gate-to-source voltage (
V
_gs
) = −6 V compared with
V
_ds
= 8.3 V and
V
_gs
= 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.