Dynamic $R_{\mathrm {ON}}$ 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 devices with 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.