ABSTRACT
The selective epitaxial growth (SEG) of Si1-xGex (0.0 ⩽ x ⩽ 1.0) on SiO2-patterned Si(lOO) substrate was investigated using the elemental source molecular beam epitaxy. The dependence of the behavior of incident Si and Ge atoms was studied on the substrate temperature and the flux. The fluxes of source beams and the substrate temperatures were in the range of 1.0 x 1013 - 2.9 x 1014 cm-2s-1 and 600 - 810°C, respectively. Under SEG condition, the Ge atoms were reevaporated from the oxide surface and were not solely effective in etching SiO2. However, Ge contributed to etch the oxide layer with accompanying Si flax. The etch rate at a Si flux of 1.0 x 1013 cm-2s-1 was about 0.85Å/min, and then increased to 1.7Å/min with accompanying Ge flux of about 2.0 x 1013 cm-2s-1. It was also shown that the SEG of Si1-xGex was achieved by the SiO2 etch due to the concurrent atomic fluxes of Si and Ge, and in part by the reevaporation of Ge atoms from SiO2 surface. The effect of source ions and electrons naturally generated from an electron beam evaporator was also investigated on the SEG characteristics of Ge. The result exhibited that the incident charged particles enhanced the nucleation of source atoms on SiO2 surface to negatively affect the SEG of Si1-xGex.n
