Ionization damage on ATLAS-SCT front-end electronics considering low-dose-rate effects

Low-dose-rate effects (LDREs) in bipolar technologies complicate the hardness assurance testing for high energy physics applications. The damage produced in the ICs in the real experiment can be underestimated if fast irradiations are carried out, while experiments done at the real dose rate are usually unpractical due to the still high total doses involved. In this work, the sensitivity to LDREs of the two bipolar technologies proposed for the ATLAS-SCT experiment in the LHC at CERN is evaluated, its magnitude measured at the total dose of interest for the transistors, and accelerated tests are performed, when necessary, on the actual ICs using high temperatures in order to mimic the effects of the low dose rate. One of the proposed technologies (DMILL) has been found free of LDREs, thus easing the radiation damage studies performed on it. The other one (CB2) suffers from LDRE. The effects have been measured for the individual devices. Experiments have been carried out to find the temperature that best mimics the LDRE at high dose rates. This temperature has been used in accelerated tests that have been performed on the chip fabricated with this technology in order to obtain the ionization damage that this IC will suffer under the real conditions.