Power devices and integrated circuits based on 4H-silicon carbide lateral JFETS

Silicon carbide (SiC) is a wide-bandgap semiconductor that has drawn significant research interest for the next-generation power electronics due to its superior electrical properties. Excellent device performance has been repeatedly demonstrated by SiC vertical power devices. However, for lateral power devices that offer the unique advantage of possible monolithic integration of a power electronics system-on-chip, the progress has been limited. This dissertation describes the 4H-SiC vertical-channel lateral JFET (VC-LJFET) technology that provides a suitable solution for power integration applications. Power devices based on this structure have a trenched-and-implanted vertical channel and a carefully designed lateral drift region, enabling normally-off operation with a high-voltage blocking capability. Low-voltage (LV) versions of VC-LJFET feature nearly identical device structures with a reduced drift length, and can be readily fabricated on the same wafer with the power devices. Essential components for a power integrated circuit, such as gate drive buffers, can be thus implemented monolithically on the VC-LJFET technology platform.;This dissertation research starts with the process improvement investigation for the TI-JFET structure. Particularly, a novel ohmic contact scheme is developed using Ni to replace the troubling process in TI-VJFETs. The entire process flow of VC-LJFET is then designed and demonstrated in experiments, leading to the world's first demonstration of a normally-off lateral power JFET in SiC. As of today, power JFETs fabricated in this technology are still representing the best-performing lateral power transistors in SiC and silicon.;Based on the VC-LJFET structure, low-voltage circuits critical to the power integration applications are investigated. Gate drive buffer provides the interface between low-voltage control circuits and the power device, and is recognized as a key component for an integrated power electronics system. A thorough design, modeling and optimization work on the LJFET-based gate drive circuits is described. These buffer drivers using resistor or transistor loads will enable high-frequency switching of the power LJFETs at megahertz levels.;The results achieved in this research strongly suggest the feasibility of SiC power integration technologies in general, as well as the suitability of the SiC VC-LJFET platform for such applications in particular.