A Quasi-Physical Compact Large-Signal Model for AlGaN/GaN HEMTs

This paper presents an accurate quasi-physical compact large-signal model for GaN high electron mobility transistors (HEMTs). The drain current Idsexpression is acquired by combining the zone division method and the surface potential theory. The proposed Idsmodel only contains 19 empirical parameters, with self-heating, ambient temperature and trapping effects considered. The self-heating effects are modeled by a polynomial function of temperature and gate voltage for the critical electric field Ec. And the ambient temperature effects are modeled by modifying pinchoff voltage and maximal electron saturated velocity. The trapping effects are considered with an effective gate-source voltage method. Moreover, taking the advantage of good physical meaning, the proposed Idsmodel is scalable. In house 0.15-μm GaN HEMTs with different sizes are used to validate the model by dc I-V over a wide ambient temperature range, pulsed I-V, multibias S-parameters up to 50 GHz and multibias large-signal characteristics at f0= 30 GHz. The good results show that the proposed quasiphysical zone division model is useful for millimeter-wave GaN HEMTs development and circuit design.