Degradation of polycrystalline silicon TFTs due to alpha particles irradiation stress

0026-2714/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.microrel.2010.07.090 * Corresponding author. Tel.: +30 210 727 6722; fa E-mail address: [email protected] (L. Michalas) The degradation mechanism of poly-Si TFTs due to alpha particles irradiation is investigated. The tested devices exhibit increase in the density of interface states and grain boundaries traps proportional to the radiation fluence, DN=N0 1⁄4 K F. The irradiation introduced defects are responsible for the degradation of major device parameters, such as the threshold voltage, the subthreshold swing, the leakage current and the ON mobility and current. Their degradation is found to obey the same law. The analysis of the thermally activated parameters reveals that the irradiation induced defects are lying deep in the semiconductor band gap. Moreover the negative threshold voltage shift is associated to positively charged oxygen vacancies in the gate insulator, called E0 centers. 2010 Elsevier Ltd. All rights reserved.