Comparison of SiC Epitaxial Growth from Dichlorosilane and Tetrafluorosilane Precursors

摘要

As a novel Si-precursor in chemical vapor deposition epitaxial growth of 4H-SiC, tetrafluorosilane (TFS) is studied for both its advantages and disadvantages. Due to its high Si-F binding energy, TFS presents exceptional ability in the suppression of parasitic deposition and Si-droplet formation during SiC epitaxial growth. As compared with epigrowth using a chlorinated precursor, dichlorosilane (DCS), growth using TFS shows a lower growth rate most likely due to the TFS etching of SiC during growth and the lower reactivity of TFS, but the quality of the TFS grown epilayers is always superior. Epigrowth using TFS also shows better control of the uniformities of epilayer surface morphology and doping concentration, which offers excellent uniformity of SiC device performance. The influence of growth conditions including temperature, gas flow rate, Si/H_2 ratio, and C/Si ratio on growth rate and epilayer properties is investigated in growth using TFS and compared with growth using DCS.