DETERMINING SI1-XGEX LAYER THICKNESS AND COMPOSITION BY ELLIPSOMETRY

The thickness and composition of Si(1-x)Ge(x) layers deposited on silicon substrates can be determined by optical ellipsometry after suitable calibration by other means, such as Rutherford backscattering. The technique is sensitive to a few tenths of a nanometre native oxide on the surface of the Si(1-x)Ge(x) layer (primarily affecting DELTA), and this oxide must be considered in using the technique.