Microstructure of SiC Prepared by Chemical Vapor Deposition

Silicon carbide prepared by chemical vapor deposition at a substrate temperature of ∼1400425‐429°C was investigated. Optical microscopy showed that the growth characteristic is dendritic; the deposits consist of columnar blocks within each of which the orientation of crystals is approximately the same. Small pores occur along the boundaries of these blocks. Transmission electron microscopy revealed finer details of the growth characteristics. The crystals were mostly 3 C in structure, but crystals with 2H and one‐dimensionally‐disordered structures were also found. The 3 C crystals are mostly dendritic, but some columnar growth with alternating twin bands occurs. Both 2 H and one‐dimensionallydisordered crystals exhibit a columnar habit, reflecting the difference in crystal symmetry from 3 C . In all these crystals, the c axis (or one of the <111> axes in 3 C crystals) lies perpendicular to the substrate.