A high-performance scintillator-silicon-well x-rays microdetector based on DRIE techniques

Abstract

This paper describes a X-rays detector based on an array of scintillator crystals, CsI:Tl, encapsulated in well-type silicon. The X-ray energy is first converted to visible light which is detected by a photodetector in the well bottom. DRIE techniques are used to achieve perfect vertical sidewalls 515 um deep, 100 um pixel square size and to maximize the fill factor. The inner walls of the well are electroplated with aluminum for improving the number of photons arriving in the detector and to reduce cross-talk between adjacent wells. Simulations and modeling show an improvement of approximately 26% in the detection efficiency using an aluminum layer 5 um thick.