Transmission electron microscopy observation of deformation microstructureunder spherical indentation in silicon

Spherical indentation of crystalline silicon has been studied using cross-s ectional transmission electron microscopy (XTEM). Indentation loads were ch osen below and above the yield point for silicon to investigate the modes o f plastic deformation. Slip planes are visible in the XTEM micrographs in b oth indentation loads studied. A thin layer of polycrystalline material has been identified (indexed as Si-XII from diffraction patterns) on the low-l oad indentation. The higher-load indentation revealed a large region of amo rphous silicon. The sequence of structural deformation by indentation in si licon has been observed with the initial deformation mechanism being slip u ntil phase transformations can take place. (C) 2000 American Institute of P hysics. [S0003-6951(00)05450-4].