Quantification of strain through linear dichroism in the Si 1s edge X-ray absorption spectra of strained Si1−xGex thin films

Abstract

We have quantitatively measured the angle dependence in the Silicon 1s X-ray absorption spectra of strained Si1−xGex thin films prepared by epitaxial growth on Si(100) substrates, through surface sensitive total electron yield detection. The linear dichroism difference extracted from these angle dependent X-ray absorption spectra is proportional to the degree of strain, as measured separately by Raman spectroscopy. This quantitative relationship provides a means to measure the compressive strain in Si1−xGex thin films. This strain-dependent X-ray absorption spectroscopy has the potential to realize a semiconductor strain metrology through high spatial resolution X-ray spectromicroscopy.