1-Grad total dose evaluation of 65 nm CMOS technology for the HL-LHC upgrades

The radiation tolerance of 65 nm bulk CMOS devices was investigated using 10 keV X-rays up to a Total Ionizing Dose (TID) of 1 Grad. Irradiation tests were performed at room temperature (25°C) as well as at low temperature (−15°C). The implications on the DC performance of n and p channel transistors are presented. For small size devices, a strong performance degradation is observed from a dose of 100 Mrad. Irradiations made at room temperature up to 1 Grad show a complete drive loss in PMOS devices, due to decreasing transconductance. When the irradiation is conducted at −15°C, the devices show less radiation damage. Annealing helps recovering a small part of the drive capabilities of the small size devices, but the threshold voltage shift is still high and might compromise the operation in some digital applications.