Thick film SOI technology: characteristics of devices and performance of circuits for high-energy physics at cryogenic temperatures; effects of ionizing radiation

We report here the characteristics of elementary devices and circuits when they are exposed at low temperature (≈ 90 K) to ionizing radiation. These devices and circuits are implemented in a radiation-hardened SOI monolithic technology. We have made irradiations both at high dose rates (≈ 100 krads/h) and low dose rate (≈ 0.02 krad/h), the low dose rate is of the order of magnitude of the value which should be encountered in high-energy physics calorimeters during future experiments. A reduction of the dose rate, at identical total dose received, has a favourable effect on the threshold voltage shift of MOSFETs and, consequently, on the behaviour of circuits designed with these devices. For example, a preamplifer remained functional with no significant change in its characteristics (noise and rise time) after ≈ 100 krads irradiation during a longer than 6 months exposure at 90 K (liquid-argon temperature). This is of key importance for the future development of silicon microelectronics for Liquid-Argon Calorimetry.