Correlation of real time spectroellipsometry and atomic force microscopy measurements of surface roughness on amorphous semiconductor thin films

We have correlated the results of real time spectroellipsometry (SE) and ex situ atomic force microscopy (AFM) measurements of surface roughness on amorphous semiconductor thin films. Roughness layer thicknesses deduced from real time SE, using a conventional approach based on the Bruggeman effective medium theory, closely obey a relationship of the form: d(s)(SE)approximate to 1.5 d(rms)(AFM)+4 Angstrom, for 10 less than or equal to d(S)(SE)<100 Angstrom, where d(rms)(AFM) is the root-mean-square roughness from AFM. The slope and intercept of this relationship provide insights into the origin and interpretation of the optically deduced roughness layer thicknesses. (C) 1996 American Institute of Physics.