Sensitivity and fading of pMOS dosemeters irradiated with X-ray radiation doses from 1 to 100 cGy

In this paper, the results of pMOS dosemeters sensitivity to X-ray radiation and 28-d fading at room temperature are presented. Two types of dosemeters were used, which differ in gate oxide layer thickness. The sensitivity of pMOS dosemeters with gate oxide layer thickness of 1 µm was followed in the dose intervals of 1 to 10 cGy and 10 to 100 cGy, whereas that of 400 nm was in the interval of 10 to 100 cGy. The sensitivity was characterised by the threshold voltage shift, which was determined as a function of absorbed radiation dose and time after irradiation. Linear dependence between threshold voltage shift and absorbed radiation dose was established, as well as that considerable fading occurs during the first few days after irradiation. The mechanisms responsible for threshold voltage shift during irradiation and latter annealing have been also discussed.