Dynamic RON of GaN-on-Si Lateral Power Devices With a Floating Substrate Termination

Dynamic ON-resistance (R-ON) of 650-V GaN-on-Si lateral power deviceswith a floating Si-substrate termination is investigated. Compared with the grounded substrate termination, the floating substrate could deliver smaller dynamic R-ON under higher drain bias (>400 V) switching operation, but leads to larger dynamic R-ON under low-drain bias (<400 V). The underlying physical mechanisms are explained by the tradeoff between charge storage in the Si substrate and electron trapping effect in the GaN buffer layer.