Radiation damage effects on p-type silicon detectors for high-luminosity operations: Test and modeling

The very high radiation fluences expected at the High Luminosity LHC (HL-LHC) impose new challenges in terms of design of effective silicon radiation detectors. To this purpose, TCAD modeling and simulation schemes, already developed and validated at typical LHC fluences, have to be adapted to take into account new effects usually neglected at lower fluences. To better understand in a comprehensive framework these complex and articulated phenomena, measurements on test structures and sensors, as well as TCAD simulations related to surface and interface effects, have been carried out. In particular, we have studied the properties of the SiO2 layer and of the Si-SiO2 interface, using MOS capacitors and gate-controlled diodes (gated diodes) manufactured on high-resistivity p-type silicon before and after irradiation with X-ray in the range from 50 krad to 10 Mrad. In this work we present the results of the experimental characterizations as well as the simulation findings, in order to validate the model and to identify the most sensitive technological and design parameters to be optimized for the design of advanced 2D and 3D silicon radiation detectors.