Growth of polycrystalline SiC films on SiO2 and Si3N4 by APCVD

The deposition of undoped and phosphorus-doped polycrystalline silicon carbide (poly-SiC) films on SiO2 and Si3N4 substrates by atmospheric pressure chemical vapor deposition (APCVD) was studied. Silane and propane were used as source gases, hydrogen was used as the carrier gas, and phosphine was used as the doping gas. The deposition temperature was fixed at 1050 degrees C and deposition times of 30 s and 30 min were used. Stylus profilometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and selected area electron diffraction (SAD) were used to compare the surface morphology and microstructure of poly-SiC films deposited on the two amorphous substrate materials, in general, doped and undoped poly-SiC films deposited on Si3N4 exhibit a smoother surface morphology and smaller grain size than doped and undoped poly-SiC deposited on SiO2. Based on the thermodynamic theory, the large grain size and rough surface texture for poly-SiC films deposited on SiO2 may be due to a higher energy barrier and larger critical nucleus size than for poly-SiC films deposited on Si3N4 These differences have been exploited to develop a lift-off patterning technique for poly-SiC films. (C) 1999 Elsevier Science S.A. All rights reserved.