Analysis of Defect-Free Hot Filament CVD-Grown 3C-SiC

Abstract

Analysis of hot-filament CVD (HF-CVD) growth of high quality 3C-SiC on micron-sized 3C-SiC mesas is presented. Two types of growth were observed: 1) a relatively slow growth at about 1μm/hour, and 2) an almost three times faster growth, correlated with the presence of domain boundaries in, or adjacent to, the mesas. Both reveal well-defined crystallographic facets and sharp corners between them. The slower growth has been identified to be surface-nucleation-limited, seemingly defect-free, while the faster growth has been identified as being caused by defect-induced step-flow growth. A growth model is presented, yielding a growth rate of 1.18 μm/h for the defect free {111} and (100) plane and 2.8 μm/h for {110} planes.

3C-SiC Island Growth on 4H-Sic Terraces: Statistical Evidence for the Orientation Selection Rule

“…A second observation is the clear triangular shape of the 3C-SiC islands, exhibiting a flat (111) top flanked by ( 100), ( 010) and (001) facets. These triangles vary in size depending on when nucleation took place and the larger ones evolve into hexagons like those observed when growing 3C-SiC on 3C-SiC mesas [8]. More relevant to our study, the triangles on the same 4H-SiC terrace align, pointing in the same direction, left or right i.e.…”

“…Growth was performed by hot-filament CVD on 4H-SiC terraces that naturally form on a 4 o offaxis 4H-SiC substrate under certain growth conditions as listed below. Hot-filament CVD has been shown to result in 3C-SiC material quality that equals that of standard CVD as based on HR-XRD and Raman measurements [8,9,10], but distinguishes itself from CVD in that precursors (silane and propane) and the carrier gas (hydrogen) are cracked by the filaments at temperatures at or above 1800 o C. The presence of the resulting atomic hydrogen causes etching during growth [11], decorating defects, while the cracking of propane occurs independent of the substrate temperature. In experiments with a single filament, we also observe a lateral variation of the carbon-to-silicon ratio and the effect it has on the surface morphology and formation -or lack thereof -of triangular defects.…”