Design and Fabrication of 1.92 kV 4H-SiC Super-Junction SBD With Wide-Trench Termination

This article presents the design and fabrication results of the silicon carbide (SiC) super-junction Schottky barrier diode (SBD). The impact of two key device structure parameters, i.e., mesa width (MW) and trench width (TW), on the device forward and reverse performance is studied by numeric simulations and measurements. Furthermore, a simple and efficient termination structure, i.e., wide-trench termination, is proposed to protect the device edge. With this termination, the simulated device breakdown voltage is significantly increased from 1423 to 2600 V with a wide-trench termination width (WTW) larger than $20~\mu \text{m}$ . The outermost MW (OMW) of the transition region is also investigated. It is found that the narrower OMW can mitigate the electric field crowding at the top of the outermost mesa and reduce the electrical stress of the dielectric. Devices with different structural parameters are fabricated and measured. The device with WTW $= 50\,\,\mu \text{m}$ and the optimum OMW demonstrates the highest breakdown voltage of 1920 V. The specific ON-resistance ( ${R}_{{\rm \scriptscriptstyle {ON}},\text {sp}}$ ) of this device is 1.6 $\text{m}\Omega \cdot $ cm ² . Subtracting the substrate resistance, the ${R}_{{\rm \scriptscriptstyle {ON}},\text {sp}}$ is only 1.2 $\text{m}\Omega \cdot $ cm ² . Such device performance successfully breaks the theoretical 1-D limit of the SiC unipolar device. Furthermore, the leakage current path of the fabricated device is investigated by thermal emission microscope (EMMI). Future improvements to reduce the leakage current are also provided.