TCAD simulation of charge collection properties of an active edge planar p-on-n sensor for FEL applications

Research at the European XFEL (X-ray Free Elec-tron Laser) needs radiation hard silicon sensors able to withstand high doses that can reach 1 GGy 12 keV x-ray radiation. To this purpose, in the aim of designing a dedicated imaging instrumentation that could cope with the tight FEL application requirements, specially regarding charge collection speed, radiation tolerance and spatial resolution, this work reports on our efforts for the development and design of a planar p-on-n sensor using a structure with an active edge. This approach helps eventually to minimize the inactive area in the edge of the sensor, and to have an optimized edge region using multiple guard ring structures for better device performance, specially in terms of a large breakdown voltage needed for the targeted application. The optimized structure and associated quasi-stationary simulations are first performed with TCAD simulations, then a study and an evaluation of the charge collection mechanism and properties is investigated in this work by means of TCAD tools. Moreover, based on simulations results obtained, devices with such opti-mized structure or configuration are fabricated. Testing of the fabricated p-on-n sensors is presented in this work.