900V Normally-OFF GaN-on-Si Transistors Achieved by Substrate Potential Modulation (SPM)

A 900-V normally-OFF GaN-on-Si transistor is demonstrated on a 650-V p-GaN-gate platform using substrate potential modulation method, without any additional EPI or process adjustment. The integration scheme can modulate the Si substrate potential between floating and grounded status, as the transistor switches from high-voltage OFF-state to low-voltage ON-state. The proposed device can simultaneously deliver higher breakdown voltage and acceptable dynamic performance. I-V and C-
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characteristics have been obtained. Reliability evaluation has been conducted to prove the 900-V blocking capability. The working principle is explained with equivalent circuit model.