Low Temperature in Situ Cleaning of Si(100) Surfaces and Transmission Electron Microscopy of Subsequent Growth of Epitaxial Germanium

Abstract

AbstractA low temperature process for cleaning Si(100) surfaces has been developed. It involves a combination of a modified hot RCA wet chemistry treatment and an in situ hydrogen treatment for the removal of oxides and carbonaceous material from the Si surface. While this treatment is successful in producing reflection high energy electron diffraction patterns which show 1/2-order reconstruction lines, subsequent Ge heteroepitaxial growth at 300°C contains a high density of microtwins. Transmission electron microscopy reveals that most of the microtwins do not propagate to the wafer surface. Furthermore, the Ge/Si interface is not abrupt, and there are regions that do not appear crystalline. This suggests that some contamination is still present on the Si(100) surface after the in situ hydrogen treatments.