Raman Microprobe Study on Relaxation of Residual Stresses in Patterned Silicon-on-Sapphire

Residual stresses in crystalline silicon islands with concave and convex corners patterned on sapphire substrate are examined by Raman microprobe technique with a spatial resolution of ~1 µm. It is found that the compressive stresses inherently remaining in SOS as-grown by conventional vapor phase epitaxy are relaxed at the edge and corners, depending on the degree of freedom in the relaxing directions.