Study on the Dynamic Ron Degradation in GaN-based Power HEMT

Dynamic on-state resistance ($\mathrm{R}_{\mathrm{o}\mathrm{n}}$) affects the competitive advantage of GaN technology versus its Si counterparts in power electronics. In this paper, we measure dynamic $\mathrm{R}_{\mathrm{o}\mathrm{n}}$ in situ during circuit operation. A special test circuit including a clamping circuit is designed. It is found that even in well-respected commercial GaN devices, dynamic $\mathrm{R}_{\mathrm{o}\mathrm{n}}$ manifests itself in various ways in circuit, which is hard to detect by traditional semiconductor parameter analyzers. One interesting find is that the gate voltage is shown to affect dynamic $\mathrm{R}_{\mathrm{o}\mathrm{n}}$ differently with different drain voltages. Brief analysis on the mechanism is provided.