Tailoring of silicon crystals through film deposition: modeling and experimental results

The present study deals with silicon crystals deformed by means of a proper film deposition and patterning. Such technique allows to realize a film-substrate system with wanted shape as a powerful tool for many technological and scientific applications. In particular, properly tailored bent crystals can be used for focusing/defocusing x-rays within the range of some tens of keV thanks to Bragg diffraction of photons [1]. More recently, interaction of high-energy charged particles with shaped crystals was intensively investigated as an alternative steering method with respect the traditional magnetic-field structures [2-4]. In this paper, we describe a technique of deposition and pattering of silicon nitride strip-like elements that enables tailoring of silicon samples to the wanted curvature for applications. Analytical and numerical results in terms of crystal deformation are compared to experimental measurement, highlighting a very good agreement between theoretical and experimental data. In particular, it will shown that the proposed analytical model represents a valid tool to accurately predict strain and stress fields in crystals deformed through a proper film deposition.