Twist-type silicon bicrystals and compliant substrates prepared from silicon-on-insulator wafers

A new approach for preparing twist-type silicon bicrystals and compliant substrates is reported. Thin single-crystal silicon films prepared from a silicon-on-insulator wafer can be bonded to each other or to silicon substrates. Thousands of silicon bicrystals bonded at different twist angles can be obtained in a single preparation process and are ready for transmission electron microscopy (TEM) examination. Plan-view and high resolution cross-sectional TEM images of the silicon bicrystals are presented. Dislocation network and moire fringes of small-angle twist-type silicon boundaries are shown. This technique facilitates the systematic study of small- and large-angle grain-boundary structures of silicon. A possible application to fabricating compliant substrates for heteroepitaxial growth of Si1-xGex is discussed.