Medium Voltage Nitride Power Transistors Enabled by Lateral Superjunction Technology (Tracking Number: 21-000001373)

Project: Research project

Project Details

Description

Wide bandgap semiconductors (WBG), e.g. SiC and GaN, have demonstrated superior performance for low voltage (below 1 kV) applications. Scaling SiC and GaN devices to medium voltage (1~35 kV) will lead to more efficient and more compact shipboard electrical systems. Critical challenges for scaling the voltage rating of the conventional WBG 1D unipolar power devices to medium voltage regime include: (1) form a thick enough drift layer to hold the standoff voltage; (2) accurately control the doping in the drift layer to allow on-state conduction while maintaining off-state blocking; and (3) manage the E-field in the drift layer.For Si power MOSFETs, scaling the voltage from sub-100-V to 600~900 V was achieved by deploying the advanced superjunction design. Similarly, WBG superjunction has the potential to scale the voltage from todays sub-1-kV range to over 10 kV. Development of SiC superjunction MOSFETs is on-going. Various GaN superjunction designs have been proposed, promising higherperformance than the SiC superjunction devices at lower cost. Successful demonstration of either vertical or lateral superjunction transistors based on GaN is yet to be achieved. This project will address fundamental technical challenges toward realizing the lateral GaN superjunction transistors.Technical approaches ofthis project are: (1) develop a sidewall gate structure to enable effective gate modulation of nitride multi-channel structure withminimal trapping effects; (2) explore factors affecting doping balance in the nitride superjunction, including: properties of lightly p-doped nitrides, control of Mg memory effects, and activation of buried p-type nitrides; and (3) investigate formation of body contact to the p-type nitride, either from the top surface or from the etched trench sidewall.Anticipated outcomes of the research include: (1) a lateral GaN superjunction transistor prototype with a blocking voltage of at least 10 kV; (2) identification of technical risks in bringing the lateral GaN superjunction transistor technology to a higher technical readiness level: and (3) identification of potential technical approaches to overcome these risks. If successful, this project will lead to ultra-low loss medium voltagepower switches. These new switches will enable shipboard electrical systems with much higher efficiency, higher power density, and lower cost.Approved for Public Release

StatusActive
Effective start/end date3/15/21 → …

Funding

  • U.S. Navy: $660,000.00

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