Papers by Author: Rahul Radhakrishnan

Abstract: Optimized design of Silicon Carbide (SiC) power devices depends, besides power device physics, also on consideration of basic properties and technological readiness of the material. This paper presents a novel analysis of the dependence of variation of epitaxial doping and thickness on the determination of the optimum design point of SiC devices. We introduce electric field at epitaxy-substrate interface as a useful parameter in controlling the dependence of device parameters on epitaxy. Using this method as criterion for design can improve the robustness of SiC devices to epitaxial variation and hence the process yield.

Abstract: Various layouts of the anode of Junction Barrier Schottky (JBS) diodes are compared theoretically and it is found that the hexagonal honeycomb structure with 3-D symmetry offers the best figure of merit (FOM). Proportional relationships between the various layouts are reported, using which we extend a fully analytical 2-D model for reverse biased field shielding in a JBS diode to the superior 3-D layouts. The effect of reducing implanted feature size is also analyzed as a trade-off between FOM and breakdown voltage capability.

Abstract: In this paper, we describe the design of a high voltage SiC VJFET monolithically integrated with a JBS diode. The integrated device that was demonstrated up to 834 V in forward blocking doesn’t add any steps to the VJFET fabrication process. While the diode and VJFET share the same surface field termination mechanism, they are partially isolated using implanted field rings. We describe TCAD based optimization of the dimensions of these field rings and outline the design of the JBS diode using a fully analytical 2-D model.