PHOTOELLIPSOMETRY - A MODULATION SPECTROSCOPY METHOD APPLIED TO N-TYPE GAAS

Photoellipsometry combines the structural sensitivity of spectroscopic ellipsometry with the built-in electric field sensitivity of photoref lectance, by measuring both the pseudodielectric function and the phot omodulated pseudodielectric function. This allows simultaneous charact erization of the built-in fields, and the structural parameters such a s heterostructure layer thicknesses on which the fields partly depend. Results for bulk n-type GaAs are presented here. Lineshape analysis, similar to that for photoreflectance, yields the surface field and dep letion width. The Schottky barrier height is also determined by analys is of the dependence on the pump beam intensity.