The effect of thermal annealing on Si/SiGe heterostructures was studied by using Raman spectroscopy. The structures consisted of Si on relaxed Si0.8Ge0.2 where the top Si thickness was 20 to 30nm. Micro-Raman spectroscopy with 488nm incident radiation revealed no significant shift in the strained Si peak position with thermal annealing at temperatures up to 1100C for 30s. However, the intensity of the Si peak was systematically reduced with increasing thermal processing, a result which was attributed to interdiffusion at the Si/SiGe interface resulting in an apparent thinning of the Si cap layer.

Effect of Thermal Processing on Strain Relaxation and Interdiffusion in Si/SiGe Heterostructures Studied Using Raman Spectroscopy. S.J.Koester, K.Rim, J.O.Chu, P.M.Mooney, J.A.Ott, M.A.Hargrove: Applied Physics Letters, 2001, 79[14], 2148-50