Effects of α-particles irradiation on polycrystalline silicon thin film transistors

The effects of alpha-particles irradiation on the electrical properties of poly-Si TFTs are investigated, through the temperature analysis of the transfer characteristics. As indicated by the thermally activated parameters, generation of states deep in the band gap usually attributed to dangling or floating bonds, is responsible for the device degradation. Therefore the OFF state leakage current and the subthreshold swing were found to increase, while the carrierspsila mobility to decrease with the radiation fluence. Furthermore a negative threshold voltage shift is observed attributed to positively charged oxygen vacancies in SiO₂ introduced by irradiation.