2004 Volume 25 Issue 9 Pages 541-547
We investigate the behavior of surface hydrogen on hydrogen-terminated (100), (110) and (111) surfaces in oxygen plasma atmosphere by using infrared absorption spectroscopy (IRAS) in multiple internal reflection (MIR) geometry. We measured the infrared absorption spectra in Si-H stretching vibration region. IRAS data demonstrated that all of the hydride species on the Si(111) surface is abstracted by oxygen plasma, and, on the other hand, a large part of the hydride on the Si(100) and (110) surfaces are abstracted but some of them are left even after a long plasma-exposure. The surface hydrogen left after the plasma-exposure is considered to be due to the migration into subsurface region where oxygen species cannot reach. Therefore, we conclude that the abstraction of the surface hydrogen by oxygen plasma does not depend on the crystallographic orientations of Si surfaces, but the migration of surface hydrogen into the subsurface region depends on the crystallographic orientations.
