High-voltage Normally-off Recessed tri-gate GaN Power MOSFETs with Low On-resistance

In this letter, we present normally-off GaN-on-Si MOSFETs based on the combination of tri-gate with a short barrier recess to yield a large positive threshold voltage (VTH), while maintaining a low specific on resistance (RON,SP) and high current density ( ID ). The tri-gate structure offered excellent channel control, enhancing the VTH from +0.3 V for the recessed to +1.4 V for the recessed tri-gate, along with a much reduced hysteresis in VTH, and a significantly increased transconductance (gm). Additional conduction channels at the sidewalls of the tri-gate trenches compensated the degradation in ON resistance (RON) from the gate recess, resulting in a small RON of 7.32 ± 0.26 Ω.mm for LGD of 15 μm, and an increase in the maximum output current ( ID max ). In addition, the tri-gate inherently integrates a gateconnected field-plate (FP), which improved the breakdown voltage (VBR) and reduced the degradation in dynamic RON. With proper passivation techniques, these devices could be very promising as high performance power switches for future power applications.

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IEEE electron Device Letters
Jun 12 2019

 Record created 2019-06-30, last modified 2019-07-02

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