Quantitative evaluation of strain near reconstructed Si surfaces

The strain fields near three different reconstructed Si surfaces, Si(1 1 1)7×7, Si(1 1 1)3×3-Ag, and Si(1 1 1)3×3-Al, were measured by using a strain-sensitive X-ray diffraction technique. The rocking curves of Si 1 1 3 reflection for these surfaces differed in peak intensity and peak width. rain fields near these surfaces were quantitatively evaluated by fitting the measured curves with curves calculated by assuming a distorted atomic layer under the reconstructed surfaces. The results show that all three reconstructed surfaces induce compressive strain in the substrates and that this strain penetrates to a depth of 10–30 nm beneath the surface. Among these three reconstructed surfaces, the 3×3-Ag surface induces the largest strain to the substrate.