Characterization of the polysilicon resistor in silicon strip sensors for ATLAS inner tracker as a function of temperature, pre- and post-irradiation

Establishing the Quality Assurance programme for the strip sensor production of the ATLAS tracker upgrade including irradiation with neutrons, photons and protons to HL-LHC fluences

“…For devices tested in ambient environment, a few cases with V bd < 500 V are observed. The full depletion voltage V fd , extracted pre-irradiation for all the pre-production batches is presented in figure 8(b), according to the QA specifications below 350 V. For verification purposes testing sites performed measurements in one pre-irradiated and one gamma irradiated at 0.66 MGy test chip, after annealing of 80 minutes at 60 • C. The bias resistor R bias structures, are identical to those on the main sensor which provide a high resistance electrical connection between the bias rail and the strip implants [11]. The R bias is extracted from the current as a function of voltage measurement.…”

“…For the pre-irradiated chips R bias is extracted with average values of 1.55 MΩ. After gamma irradiation all of the three resistors tested with R bias average of 2.16 MΩ, the measurements performed at −20 • C [11]. In figure 9(a) the current as a function of voltage measurements of the bias resistor structures on the site verification test chips (one pre-irradiated, one gamma irradiated) is presented.…”