Behavior of $CaF_2$ at the Initial Adsorption Stage on Si(114)

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  • 김희동 (전북대학교 물리학과 및 광전자정보기술연구소) ;
  • 서재명 (전북대학교 물리학과 및 광전자정보기술연구소)
  • Published : 2012.02.08

Abstract

From the combined studies of STM and synchrotron photoemission, it has been found that a $CaF_2$ molecule is dissociated to Ca and F atoms on the $Si(114)-2{\times}1$ held at $500^{\circ}C$ at the initial adsorption stage. The Ca atoms form isolated and unique shapes of silicide molecules as shown in Fig. (a), while the F atoms are desorbed from the surface. On the other hand, beyond a $CaF_2$ coverage of 0.3 monolayer, as shown in Fig. (b), in addition to these silicide molecules, a 1-D facet [composed of (113) and (115) faces] adjacent to an etch pit has been observed, and F atoms are also detected from photoemission. These results imply that F atoms act as an etchant on Si(114) and CaF is adsorbed selectively on the (113) face of this facet. From the present studies, it has been concluded that, an insulating $CaF_2$ layer like that on Si(111) cannot be formed on Si(114), but a CaF-decorated nanofacet with a high aspect-ratio can be grown.

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