TRIPLE CRYSTAL X-RAY-DIFFRACTION ANALYSIS OF CHEMICAL-MECHANICAL POLISHED GALLIUM-ARSENIDE

High-resolution triple crystal x-ray diffraction has been used to monitor the magnitude of diffuse scattering from chemical-mechanical (CM) polished GaAs. The diffuse scattering, which is attributed to kinematic scattering arising from polish-induced crystallogiraphic defects, was found to be only slightly affected when each of four CM polish parameters (bromine concentration in Br2/methanol, total polish time, polish pad rotation speed, and force on sample) was varied individually. The combined effect of increases in both the pad rotation speed and the force on the sample increased the magnitude of the diffuse scattering, suggesting the generation of mechanical damage. When all four variables were increased to their values, the diffuse scattering increased dramatically and became anisotropic. We have the magnitude of the diffuse scattering in terms of an "excess intensity" in reciprocal provide a semi-quantitative relation between CM polish parameters and the generation of polish-induced damage.