Influence of the Crystal Characterization of CsI Thin Film for X-ray Image Detectors

摘要

Powder CsI crystal has been deposited with vacuum thermal evaporation on three different kinds of substrates: Si, SiO_2/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.