EPITAXIAL-GROWTH AND ELECTRICAL CHARACTERISTICS OF BETA-SIC ON SI BY LOW-PRESSURE RAPID THERMAL CHEMICAL-VAPOR-DEPOSITION

The structural and electrical properties of beta-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 SiH4 (5% in H-2) and C3H8 (5% in H-2) from 1100 to 1250 degrees 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 degrees for Si/C ratio of 0.4-0.7. An epitaxial SiC thickness up to 8 mu 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 Omega . 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 beta-SiC epilayers. The optimum growth temperature and Si/C ratio were 1150 degrees C and 0.6, respectively.