ANGULAR SPECTROSCOPIC ANALYSIS - AN OPTICAL CHARACTERIZATION TECHNIQUE FOR LATERALLY OXIDIZED ALGAAS LAYERS

We present an optical characterization technique to determine both the refractive index and the shrinkage of laterally oxidized AlAs and AlG aAs layers. The technique consists of measuring the angular dependence of the Fabry-Perot dip wavelength in a simple cavity structure. Over standard ellipsometry, it has the advantage of measuring more realisti c layer structures. Over transmission electron microscopy cross sectio ns to determine the final aluminum-oxide layer thickness, it has the b enefit of performing the measurement without elaborate sample preparat ion. We find that AlAs shrinks by approximately 3% during oxidation, a nd that the refractive index of oxidized AlAs is 1.52. (C) 1997 Americ an Institute of Physics.