AFM Observation of the Surface Morphology of CaF2 Film Grown on Si(111) 7*7 Substrate.

Abstract

Surface morphology of CaF2 film grown up to 500 Å thickness on a Si(111) 7×7 substrate in the temperature range from room temperature (RT) to 700oC has been observed by atomic force microscopy (AFM) and reflection high-energy electron diffraction (RHEED). It was found that three dimensional (3 D) islands of CaF2 were grown at RT, however, relatively flat surface appears at over 300oC. Especially, at a high temperature of 700oC, equilateral triangular shape islands with wide flat terrace were formed. On the other hand, desorption process of the CaF2 film due to electron stimulated desorption (ESD) was also investigated. It was found as a remarkable point that equilateral triangular shape craters were formed on the film surface at 300oC by ESD.