Spontaneous step creation on (001) silicon surfaces studied with scanning tunneling microscopy and low-energy electron microscopy.

摘要

ltra-high vacuum (UHV) scanning tunneling microscopy (STM) and low-energy electron microscopy (LEEM) were used to make the first conclusive and direct observation of a striped step phase on silicon (001) surfaces induced by a substrate imposed biaxial tensile strain and/or heavy boron doping.;For 5nm silicon (Si) films grown on relaxed silicon-germanium (SiGe) substrates, stable wavy-step structures in which large amplitude, periodic ;Heavily B-doped Si(001) surfaces are also observed to form finely striped step structures (;The shape of the structures observed for both Si/SiGe(001) and B-doped Si(001), are consistent with recent isotropic elastic calculations, which show the same progression of step structures from straight-triangular-tiled-striped, as the terrace width, surface stress anisotropy, or biaxial tensile strain is increased.;LEEM and STM have also been used to image residual uniaxial strain fields on SiGe(001) films, and a high degree of correlation was found between lateral strain variations and the surface cross-hatch morphology on strain-relaxed