The heteroepitaxial growth of contiguous monocrystalline films is facilitated by the initial and separate chemical conversion of the Si(100) surface via reaction at elevated temperatures with a hydrocarbon gas entrained in . The initial and subsequent reactions produce a very thin film of . Sealing of the initial growth defects and continued pyrolysis of the hydrocarbon combine to both limit the thickness of this film and result in the formation of free C on the final surface. Reflection (high energy) electron diffraction and optical, scanning, and cross‐sectional transmission electron microscopies revealed the films to be generally monocrystalline but containing regions of disorder as well as pyramidal‐shaped pits, mismatch dislocations, stacking faults, and residual strain. The empirically determined optimum conversion time of 150s was supported by x‐ray photoelectron spectroscopy (XPS) which indicated the aforenoted formation of free C after longer periods. The effects on the XPS results of heating or Ar+ sputtering to remove surface hydrocarbons and oxide were also investigated.