Epitaxial growth and electrical characteristics of β-SiC on Si by low-pressure rapid thermal chemical vapor deposition

The structural and electrical properties of β-SiC thin films grown on a (100) Si substrate by low pressure rapid thermal chemical vapor deposition (LP-RTCVD) at as low as 2.5 Torr are reported. SiC growth was achieved by the reaction of SiH 4 (5% in H 2 ) and C 3 H 8 (5% in H 2 ) from 1100 to 1250° C. The structural properties of SiC thin films were investigated by X-ray diffraction and scanning electron microscope (SEM) analysis. The X-ray diffraction shows that the full width at half-maximum (FWHM) is 0.34-0.35° for Si/C ratio of 0.4-0.7. An epitaxial SiC thickness up to 8 µ m was also observed by SEM. The unintentionally doped SiC film is n-type with electron mobility of 132-254 cm 2 /V·s for carrier concentration around 10 17 cm -3 and resistivity 0.08-0.3 Ω· cm, based on both four-point probe and Hall measurements. To our knowledge, the measured mobility is the highest of those reported for low-pressure CVD-grown β-SiC epilayers. The optimum growth temperature and Si/C ratio were 1150° C and 0.6, respectively.