Fast and Accurate Temperature-Dependent DC Model for GaN HEMT Devices

In last years, Gallium Nitride (GaN) high-electron-mobility-transistor (HEMT) has emerged as an at-tractive solution to reduce considerably power losses in tran-sistor switch used in power electronics. In this paper, we pre-sent a simple and accurate temperature-dependent static ana-lytical model for the GaN HEMT, suitable for circuit simula-tor. The proposed model is based on the alpha-power law MOSFET model which was introduced to improve the first-level MOSFET models. In this work, temperature dependence of the model is obtained by its temperature scaling parame-ters. On the one hand, the model takes into account the peculi-ar features observed in transfer characteristic of GaN HEMT at different temperatures: a) the rapid increase of drain cur-rent versus gate voltage at low gate voltage, b) the quasi-saturation effect, which occurs at high gate voltage by the limi-tation of drain current increase versus gate voltage. On the other hand, the model is compatible with high voltage GaN HEMT which shows a gradual increase of the drain current in its output characteristics contrarily to low voltage GaN HEMT. The model parameters are extracted by using an op-timizer algorithm in order to fit model to experimental data in all operating regions of device. Good initial guess values of pa-rameters, extracted from experimental data, are used to lead rapid convergence of the optimizer algorithm. The reduced number of model equations and parameters allows a fast simulation and an easier implementation of the model in cir-cuit simulator. Finally, the accuracy of the proposed model is demonstrated by comparing model to datasheet and experi-mental data of GaN HEMT static I-V characteristics.