Temperature-dependent dynamic RDS,ON under different operating conditions in enhancement-mode GaN HEMTs

Abstract

High-voltage enhancement-mode (E-mode) gallium nitride (GaN) high electron mobility transistor (HEMT) is a superior candidate to enable higher efficiency and higher power density when compared with silicon power devices in power converter applications. However, the dynamic RDS,ON problem affects the conduction loss of the converter and remains one of the major issues that must be resolved. In this study, a comprehensive experimental evaluation and analysis method of the temperature-dependent dynamic RDS,ON of GaN HEMT in a circuit level is proposed. A commercial E-mode GaN HEMT (GS66508T) is used as a sample to study the temperature-dependent dynamic RDS,ON using a double-pulse-tester. The temperature-dependent dynamic RDS,ON under different DC-link voltages and different load currents are studied and the results show a non-monotonic temperature-dependence of the dynamic RDS,ON. It is concluded that the temperature dependence of the buffer-induced trapping and de-trapping effect, and the temperature dependence of electron mobility together influence the dynamic RDS,ON of E-mode GaN HEMT device during operation. This finding is important since in converter applications the devices are typically operating at elevated temperatures. The proposed comprehensive experimental method can be used to estimate and analyse the dynamic RDS,ON characteristics of other GaN devices.