Fast Homoepitaxial Growth of 4H-SiC Films on 4° off-Axis Substrates in a SiH₄-C₂H₄-H₂ System

Homoepitaxial growth of 4H-SiC epilayers is conducted in a SiH₄-C₂H₄-H₂ system by low pressure hot-wall vertical chemical vapor deposition (CVD). Thick epilayers of 45 μm are achieved at a high growth rate up to 26 μm/h under an optimized growth condition, and are characterized by using a Normaski optical microscope, a scanning electronic microscope (SEM), an atomic force microscope (AFM) and an x-ray diffractometer (XRD), indicating good crystalline quality with mirror-like smooth surfaces and an rms roughness of 0.9 nm in a 5 μm × 5μm area. The dependence of the 4H-SiC growth rate on growth conditions on 4° off-axis 4H-SiC substrates and its mechanism are investigated. It is found that the H₂ flow rate could influence the surface roughness, while good surface morphologies without Si droplets and epitaxial defects such as triangular defects could be obtained by increasing temperature.