Effect of hydrogen on Cu formation on Si(111)

Cu formation processes on clean Si(111)-(7 x 7) and hydrogen-terminated Si(111) surfaces have been investigated in situ by means of a medium-energy ion scattering (MEIS), RHEED, AES and observed ex situ with a field emission-scanning electron microscope (FE-SEM). The non-uniform Cu films including Si atoms are formed on the Si(111)-(7 x 7) surface at room temperature and the ''5 x 5'' incommensurate structure can be observed on the Cu/Si(111) at high temperature (130-600 degrees C). On the hydrogen-terminated Si(111) surface at room temperature, the growth processes of Cu are not so different from those on the clean Si(111)-(7 x 7) surface. However, the formation processes of Cu on the hydrogen-terminated Si(111) surface at high temperature (similar to 300-500 degrees C) are quite different from those on the bare Si(111)-(7 x 7) surface. Cu atoms can easily migrate on the hydrogen-terminated Si(111) surfaces and form tall islands. The hydrogen-terminated surfaces remain, and can be observed by means of RHEED and SEM.