Amorphization/templated recrystallization method for changing the orientation of single-crystal silicon: An alternative approach to hybrid orientation substrates

摘要

We demonstrate that the crystal orientation of single-crystal silicon layers may be changed in selected areas from one orientation to another by an amorphization/templated recrystallization (ATR) process, and then introduce ATR as an alternative approach for fabricating planar hybrid orientation substrates with surface regions of (100)- and (110)-oriented Si. The ATR technique, applied to a starting substrate comprising a thin (50-200 nm) overlayer of (100) or (110) Si on a (110) or (100) Si handle wafer, consists of two process steps: (ⅰ) Si~+ or Ge~+ ion implantation to create an amorphous silicon (a-Si) layer extending from the top of the overlayer to a depth below the overlayer/handle wafer interface, and (ⅱ) a thermal anneal to produce the handle-wafer-templated epitaxial recrystallization of the a-Si layer. Regions exposed to the ATR process assume the orientation of the handle wafer while regions not exposed to the ATR process retain their original orientation. The practicality of this approach is demonstrated with the fabrication of a planar hybrid orientation substrate comprising (100) and (110) Si regions separated by SiO_2-filled trenches.