Si deposition into fine contact holes by ultrahigh-vacuum chemical vapor deposition

An ultrahigh-vacuum chemical vapor deposition technique with disilane (Si2H 6) molecular flux is applied to fine contact hole filling. Structural obser vations reveal that a completely buried Si contact has a stacked structure, in which the lower portion consists of pyramidal epitaxial Si, whose heigh t depends not only on the growth temperature and the Si2H6 flow rate but al so on the hole diameter, and polycrystalline Si is deposited on the epitaxi al Si. The mechanism of selective epitaxy is interpreted in terms of incuba tion time and facet growth rate depending on growth temperature and Si2H6 f low rate.