Modeling the Response of the ESAPMOS4 RADFETs for the ALPHASAT CTTB Experiment

The Component Technology Test-Bed (CTTB) is one of the main components of the ALPHASAT spacecraft radiation Environment and Effects Facility (AEEF), an European Space Agency (ESA) Technology Demonstration Payload. In-flight data collected by the CTTB experiments will be used to validate ground test protocols, perform prediction models for new component technologies and to provide in-flight evaluation of critical component technologies for use in future missions. The relation between the RADFETs gate threshold voltage shift and the dose can strongly depend on the production processes parameters and needs to be experimentally determined before its use in space. A calibration test campaign of ESAPMOS4 RADFETs was conducted at the ESA/ESTEC Cobalt-60 facility. Irradiation runs were performed at three nominal temperatures: room temperature, 60°C, and 80°C. After the irradiation runs, the units underwent annealing, under similar temperature and bias configuration settings. A model capable of describing the RADFET temperature dependent response during irradiation, at low and high dose rate regimes, is presented in this paper, along with the analysis of the RADFET response during isothermal annealing, following irradiation.