SiC/Si(111) film quality as a function of GeH4 flow in an MOCVD reactor

Due to large lattice and thermal expansion coefficient mismatches, SiC film s grown on Si are usually low quality. To provide a more stable growth fron t we added Ge in the form of GeH4 to the reactant gases in a MOCVD reactor. Several SiC films with Ge flow rates ranging from 0-50 seem were grown on (111) Si substrates at 1000 degrees C. TEM results show that the crystallin e quality is amorphous or polycrystalline for Ge flow rates at or below 15 sccm. Samples grown at Ge flow rates at or exceeding 20 sccm have an initia l layer of single crystalline 3C SiC followed by heavily twinned crystallin e 3C SiC. In particular, the samples grown with 20-30 seem Ge contain an 80 nm initial layer of reasonably high quality single crystal 3C SiC.