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 Compact GaN-based Bidirectional Polarization Super Junction HFETs with Schottky Gate on Sapphire

Authors & Affiliations

Xiao Tan and Ekkanath Madathil Sankara Narayanan
Department of Electronic and Electrical Engineering
The University of Sheffield
United Kingdom



 Performance evaluation of compact GaN-Based Bidirectional Polarization Super-Junction Heterojunction Field Effect Transistors with Schottky Gate (Bi PSJ SG HFET) fabricated on the sapphire substrate is presented in this paper. The on-state performance under various bias conditions is simulated and measured, and the operating mechanisms are analysed. Measured electric characteristics of fabricated Bi PSJ SG HFETs show symmetrical characteristics in the first and third quadrants, successfully realizing the bidirectionality. The logic function of the on-state performance of Bi PSJ HFETs is summarized. Numerical simulations show that a device can withstand high blocking voltages with a “box” like electric field in the common drift region. The measured average area-specific on-state resistance Ron. A of a Bi PSJ SG HFET is 64 mΩ.cm2 in both directions at room temperature for a device with a 40µm length of PSJ. In addition, temperature dependence on the area-specific on-state resistance of Bi PSJ SG HFETs with 40μm is also measured. Using analytical models of on-state resistance, the Ron. A is calculated and fit well with measured results with different PSJ length.


GaN; Polarization Super Junction; bidirectional switch

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