Influence of structural defects on thermostability and radiation sensitivity of Si MOSFET dosimeters

The metal oxide semiconductor field effect transistor (MOSFET) dosimeters have recently become commercially available. For this reason, it is not surprising that the study of radiation interactions with MOS materials, devices, and circuits has been a major theme of many articles. The purpose of this study was to investigate the influence of structural defects on thermostability and radiation sensitivity of Si MOSFET dosimeters. It was shown that the near-surface layers of silicon have a complex defective structure which consists from the disordered layer of silicon and the layer of dislocation networks. Grain boundaries of disordered layer form additional energy levels close to the midgap of silicon. These states are ionized under radiation effect and form positive charge. This positive radiation-induced charge becomes additional to the oxide charge and it changes (increases) radiation sensitivity of Si MOSFET detectors. However, these states are the additional source of charge carriers under temperature increasing and lead to changing of detector’s parameters.