Ion channeling studies of preferentially (111) oriented BaF2films on amorphous SiO2substrates

摘要

The crystalline quality of preferentially (111) oriented BaF2films grown on amorphous SiO2has been investigated by ion channeling measurements, as well as xhyphen;ray diffraction analyses and transmission electron microscopy (TEM). The films are grown by vacuum deposition onto heated (500ndash;750thinsp;deg;C) Si substrates covered with SiO2films. It has been found that the channeling effect of MeV ions occurs in BaF2films on SiO2and that the minimum yield in the films grown at 700thinsp;deg;C is as low as 9percnt; near the surface. It has also been observed by TEM and xhyphen;ray analyses that the average size of the crystallites and the spread of the crystallite orientation in the good films are about 400 nm and 0.4deg;, respectively.