Monolithic Integration of SiC Power BJT and Small-Signal BJTs for Power ICs

Abstract

Monolithic integration of power transistor and specific functional integrated circuits (power ICs) offers unique advantages for wide bandgap power devices. However, few publications have reported the power ICs based on SiC because of several challenging problems such as fabrication process and cost. This paper explores the monolithic integration possibility of 4H-SiC lateral small-signal bipolar junction transistors (BJTs) and vertical power BJT without extra mask or processing step other than Vanadium isolation implantation. A new monolithic power integration architecture is proposed and optimized using TCAD simulations first, and then both the vertical and lateral SiC BJT types are fabricated on the same wafer using the standard power BJT process to experimentally verify the feasibility of the monolithic integration method. The SiC power BJT demonstrates a breakdown voltage of 1320 V and a peak common-emitter current gain of 13.1 while the lateral SiC BJT demonstrated a breakdown voltage of 25 V and a peak common-emitter current gain of 3.8 at room temperature. While the device performance can be further improved, the fact that they can be successfully fabricated on the same wafer without much process modification shows a great promise of realizing monolithic SiC power ICs, which will greatly benefit the next-generation power electronics systems.