全反射臨界角近傍でのX線回折法によるシリコン結晶中の微小格子歪の観察・評価

概要

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Abstract As dynamic random access memories and imaging devices continue to be made smaller, the quality of the silicon surfaces on which they are made becomes more and more important. The surface damage introduced by mechanochemical polishing is reported as one of the causes that degrade a device performance. For this reason, powerful characterization techniques for surface damage are strongly required. As the one method, X-ray topography using extremely asymmetric diffraction under the simultaneous diffraction condition is effective for imaging a minute strain field near the surface. In the present study, characterization of the minute strain field in silicon crystals with oxide film of 5nm and 25nm thick was performed using extremely asymmetrical X-ray diffraction of 311 reflection using the Berg-Barrett method and the double-crystal method. A series of X-ray topographs were taken around the Bragg peak and off-Bragg angles on both sides of incident angle. The reverse contrast was observed between topographs taken at strain field occurring at both sides of oxide film of 5nm thick and surface defect images arising from the mechanochemical polishing were clearly visualized.
宮崎大学の論文