Powder CsI crystal has been deposited with vacuum thermal evaporation on three different kinds of substrates:
Si, SiO2/Si and Pt/Si. We have analyzed and observed these CsI films with different depth and various preparation
conditions by XRD measurement. Through analyzing, we find that in such process condition the crystal state of
CsI film has a strong relationship with the crystal structure of substrate, and non-crystal substrate goes against
crystallization. By contrasting standard XRD diagram of CsI(Tl), we discover that with the influence of the surface
structure of substrate, CsI crystal film has a preferred orientation in (200) crystal face. We also notice that the
preferred orientation of CsI film has a close relation with the depth of the film: the preferred orientation has been
weakened as the depth of film turning from 70μm to 100μm.