High quality Ge epitaxial layers in narrow channels on Si (001) substrates

We demonstrate the selective growth of high quality Ge epitaxial layers in channels as narrow as 10 nm on patterned Si (001) substrates by a combination of low temperature growth and selective recrystallization using Ge melt and regrowth during a millisecond laser anneal. Filling narrow trenches at high growth temperature as required for obtaining high quality layers was shown to be prohibited by Ge outdiffusion due to the high Ge chemical potential in such narrow channels. At low temperature, a hydride-terminated surface is maintained which counteracts the outdiffusion of the Ge adatoms and provides excellent trench filling. The resulting low crystalline quality can be restored by a selective Ge melt and epitaxial regrowth using a millisecond laser anneal.