Bulk growth of high-purity 6H-SiC single crystals by halide chemical-vapor deposition

High-purity 6H-SiC single crystals were grown by the halide chemical-vapor deposition process. Growth was performed in a vertical hot-wall reactor with a separate injection of a silicon precursor (silicon tetrachloride) and a carbon precursor (propane). Typical growth rates were between 100 and 300 μmh. The crystals contain very low concentrations of residual impurities. The main contaminants, namely, nitrogen and boron, are in the 1014 atoms cm-3 range. Crystals grown under Si-rich conditions were n type with low room temperature electron concentrations in the 1014 - 1015 atoms cm3 range and with room-temperature electron mobilities approaching 400 cm2 V s. The resistivity of the material increased up to 1010 Ω cm with increasing CSi ratio. Deep levels spectra show that the electron traps density decreases with increasing CSi ratio.