Study on the Mechanism of Facet Formation Based on the Shape of Temperature Field

Abstract

This paper presents a systematic study of the facet formation on the wafer surface at the end of large-diameter 4H-SiC crystal growth, guided by numerical simulations. The influence of different temperature field shapes on facet position and shape was examined through resistivity tests and wafer scanning. Various models were developed to explain these effects, with facet shape changes ultimately interpreted through thermodynamic principles. Facets were found to form when the basal plane is tangent to the growth interface. The convexity K is directly proportional to the position P of the facet from the edge. The appearance of double facets on the same side due to large convexity K₁, confirms that the temperature field shape is a critical factor in determining the facet position. The facet shape can be viewed as a cross-section formed by the intersection of the basal plane and the growth interface. The length of the facet H is inversely related to the crystal convexity K. Both the width of the facet D and the inner angle θ are significantly influenced by the convexity K₁. As the convexity K₁ increases, the inner angle θ decreases, while the width D increases.