The role of dissolved oxygen in hot water during dissolving oxides and terminating silicon surfaces with hydrogen

Evidence of the removal of surface oxides from a partially oxidized Si(111) surface, and the simultaneous termination of the new dangling bonds by hydrogen in hot water, has been obtained. The amount of remaining oxides decreased by lowering the dissolved-oxygen concentration (DOC) from 4 to 0.004 ppm. After immersing in hot water with a DOC of 0.004 ppm for 60 min, almost all of the surface was hydrogen-terminated and only a tiny amount of silanol groups remained. The appearance of vertical dihydrides at step edges showed that the oxidation process on the hydrogen-terminated surface continues, even in water with a DOC of 0.004 ppm.