Effects in Silicon Explained by Atomic Hydrogen

Abstract

ABSTRACTThe chemomechanical polishing mechanism is described as a corrosive attack of water forming Si-H and Si-OH groups. By adding ammonia or amines to the slurry we observe an irlfease of the resistivity corresponding to a neutralization of up to 1 × 1017 acceptor atoms cm−3 in the case of p-type silicon, whereas n-type silicon can show a slight reduction in resistivity due to the neutralization of the residual acceptor concentration.SIMS measurements show the presence of hydrogen in the bulk. Using deuterium instead of hydrogen, a correlation could be established between the deuterium content of the wafer, measured by the effusion technique, and the degree of the acceptor compensation.As can be shown by resistivity and C/V-measurements, under the conditions of polishing the supposed inactivator hydrogen migrates to a distance finally corresponding to the thickness of a wafer. This is contrary to the comm on method of plasma treatment, where a damaged silicon layer is supposed to act as a barrier to the hydrogen diffusion. Differences in the IR spectra can be explained this way.Crystal imperfections in the bulk and on the surface influences the migration of hydrogen essentially.