Performance limits of 4H-SiC and 2H-GaN vertical superjunction (SJ) devices

Abstract

In our performance limits projections of stripe-cell superjunction devices (STR-SJ), the specific on-resistances are 0.1 mΩ-cm2 and 1 mΩ-cm2 for 4H-SiC and 0.03 mΩ-cm2 and 0.3 mΩ-cm2 for 2H-GaN with blocking voltages of 1kV and 10kV respectively. Specific on-resistances are 3X and 100X lower than the unipolar 1D limits. Specific on-resistances are 0.03 mΩ-cm2 and 0.3 mΩ-cm2 respectively for 4H-SiC and 0.01 mΩ-cm2 and 0.1 mΩ-cm2 for 2H-GaN of hexagonal layout design (HEX-SJ). HEX-SJ devices can improve Ron,sp by 3X compared with STR-SJ. For GaN, we have obtained much better performance on the vertical natural polarization superjunction (PSJ) devices based on the AlGaN/GaN and AlInN/GaN heterostructures than that for the conventional superjunction devices with alternating p/n pillars. Specific on-resistance of AlGaN/GaN and AlInN/GaN PSJ devices can be as low as 0.06 µΩ-cm2 and 0.6 µΩ-cm2 for BV of 1kV and 10kV respectively. The performance is 1500X and 50000X better than the unipolar limits of GaN devices.

We have determined and evaluated the specific on-resistance (Ron,sp) versus breakdown voltage (BV) tradeoff limits of high-voltage, vertical superjunction (SJ) devices for 4H-SiC and 2H-GaN. Those vertical superjunction devices include conventional p/n doped superjunction devices and novel natural polarization superjunction (PSJ) devices. We have employed a previously published analytical model for the superjunction devices with alternating P and N doped pillars. We have also identified and replaced some unreasonable assumptions in another previous work. Further, this thesis is the first time the performance limits projected for natural polarization superjunction devices.