4H–SiC homoepitaxy on nearly on-axis substrates using TFS-towards high quality epitaxial growth

• We report high quality nearly on-axis SiC growth with a two regime growth model.
• Unique etching and chemical reactions of a novel Si precursor are explained.
• Conditions for 3C, spiral and uniform step flow epilayer growth are discussed.
• New reaction pathways at C rich conditions to obtain step flow growth highlighted.

We report high quality homoepitaxial growth on nearly on-axis (±0.5°±0.5°) 4H–SiC substrates by chemical vapor deposition (CVD) using Tetrafluorosilane and Propane as Si and C-precursors, respectively. N-type unintentional doping (1017–1014 cm−3) was obtained for 0.62.0, a linear dependence on C-flow is established, with a return to step-mediated growth, shown by the surface morphology (RMS roughness ∼1 nm), and high polytype uniformity from Raman at high Rg- 14 μm/h. These two behaviors were ascribed to a decrease in the etch rate of SiC by SiF4 with increasing C/Si due to C-aided decomposition of SiF4, both of which make available a greater amount of elemental Si at the surface, thereby suppressing spiral growth. Use of on-axis or near on-axis substrates can eliminate/reduce basal plane dislocations which limit the performance of SiC bipolar electronic devices.