A charge collection study with dedicated RD50 charge multiplication sensors

This study investigates the charge collection efficiency of silicon strip detectors, produced by MICRON Semiconductor Co., Ltd. within the CERN RD50 collaboration, designed specifically to understand the effect of design parameters on the onset and magnitude of charge multiplication. Charge collection measurements are performed before and after irradiation with a proton fluence of 1×1015 1 MeV neq/cm2 (neq/cm2) and neutron fluence ranging from 1–5×1015 neq/cm2. Structures on these devices include varying diffusion times and energies for the implantation process, different sensor thicknesses, the use of intermediate biased or floating strips between the readout strips, and several different strip width and pitch geometries. The charge collection for these devices is studied as a function of the bias voltage, looking for indications of charge multiplication. Results are compared to standard float zone 300μm thick silicon strip sensors having a strip width of 25μm and pitch of 80μm. -- Highlights: •Specially designed silicon detectors were developed to investigate charge multiplication. •Charge collection measurements were performed before and after irradiation. •Charge multiplication only seen ≥5×1015neq/cm2. •Decreasing width/pitch increases collected charge. •Increasing implant energy/diffusion time increased collected charge