On the mechanism of chemical polishing of GaAs crystals |
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Authors: | D. Zach,H. Lö we |
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Abstract: | In order to establish reproducible conditions for chemical lap polishing of GaAs with NaOCl solutions, containing also OH−- and CO -ions, the mechanism of dissolution was investigated using the rotating disk arrangement. In solutions with excess OCl− concentrations likewise diffusion and a reaction of the first order with respect to OH− and CO, complexing agents for Ga-ions, control the dissolution rate, and the surfaces of the wafers are polished. OH− and CO32– concentrations in excess with respect to OCl− lead to rate determining OCl− diffusion and to irregularly polished or film covered surfaces. Diffusion constants for OH−, CO and OCl− are given. |
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