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 <inline-formula> <tex-math notation="LaTeX">$I_{\mathrm {ds}}$ </tex-math></inline-formula> expression is acquired by combining the zone division method and the surface potential theory. The proposed <inline-formula> <tex-math notation="LaTeX">$I_{\mathrm {ds}}$ </tex-math></inline-formula> model 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 <inline-formula> <tex-math notation="LaTeX">$E_{c}$ </tex-math></inline-formula>. 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 <inline-formula> <tex-math notation="LaTeX">$I_{\mathrm {ds}}$ </tex-math></inline-formula> model is scalable. In house 0.15-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaN HEMTs with different sizes are used to validate the model by dc <inline-formula> <tex-math notation="LaTeX">$I$ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> over a wide ambient temperature range, pulsed <inline-formula> <tex-math notation="LaTeX">$I$ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula>, multibias S-parameters up to 50 GHz and multibias large-signal characteristics at <inline-formula> <tex-math notation="LaTeX">$f_{0} = 30$ </tex-math></inline-formula> GHz. The good results show that the proposed quasi-physical zone division model is useful for millimeter-wave GaN HEMTs development and circuit design.