Fast-filling of 4H-SiC trenches at 10 μm/h by enhancing partial pressures of source species in chemical vapor deposition processes

Abstract

4H-SiC trenches with depths of approximately 25 μm were filled under a special condition called the quasi-selective epitaxial growth mode that showed a refill-rate of 2.1 μm/h within 12 h, using a hot-wall chemical vapor deposition (CVD) method with the assistance of HCl gas. To develop a high-rate growth mode for the 4H-SiC trench filling process, several CVD growth parameters, such as the flow rates of source gases, HCl and H2 carrier gases, their pressures, and the applied C/Si ratio, were regulated and optimized, to enhance the partial pressures of the source species in the gas phase of the CVD reactor. A refill-rate of 11.4 μm/h in 2 h was achieved, which is nearly five times faster than the initial growth.