A Calibrated Electro-Thermal TCAD Model for Predicting Pulsed I-V and Self-Heating in p-GaN HEMTs
ORAL
Abstract
Accurate modeling of Gallium Nitride (GaN) HEMTs for power and RF applications is critical, where performance is limited by dynamic trapping phenomena and self-heating effects. We present a TCAD calibration methodology to develop a physically-based model capable of reproducing experimental pulsed I-V characteristics of a p-GaN enhancement-mode HEMT.
Our approach first defines the linear-region characteristics by tuning material properties that govern charge transport. The ideal 2DEG sheet density (ns) is established by tuning the AlGaN mole fraction, which defines the maximum theoretical current. Then, acceptor trap concentrations in the GaN channel are systematically increased to introduce charge compensation, accurately matching the degraded on-resistance and linear slope seen in experimental data.
With the linear behavior set, the saturation current is calibrated by adjusting key geometrical parameters, primarily the p-GaN gate and AlGaN barrier thicknesses. This approach modulates the gate's electrostatic control over the channel, influencing current and velocity saturation at high drain bias. This geometrical tuning is performed in conjunction with calibrating the device's thermal impedance to account for self-heating induced current droop. The successfully calibrated model serves as a robust digital twin, enabling predictive analysis and exploration of novel device geometries for next-generation pulsed power systems.
Our approach first defines the linear-region characteristics by tuning material properties that govern charge transport. The ideal 2DEG sheet density (ns) is established by tuning the AlGaN mole fraction, which defines the maximum theoretical current. Then, acceptor trap concentrations in the GaN channel are systematically increased to introduce charge compensation, accurately matching the degraded on-resistance and linear slope seen in experimental data.
With the linear behavior set, the saturation current is calibrated by adjusting key geometrical parameters, primarily the p-GaN gate and AlGaN barrier thicknesses. This approach modulates the gate's electrostatic control over the channel, influencing current and velocity saturation at high drain bias. This geometrical tuning is performed in conjunction with calibrating the device's thermal impedance to account for self-heating induced current droop. The successfully calibrated model serves as a robust digital twin, enabling predictive analysis and exploration of novel device geometries for next-generation pulsed power systems.
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Presenters
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In Jun Park
- National Institute of Standards and Technology