Simulation of charge processes in dielectric films of MIS structures at simultaneous influence by ionization and high-field injection of electrons

Use of High-Field Electron Injection into Dielectrics to Enhance Functional Capabilities of Radiation MOS Sensors

“…The reducing of the MOS sensor dose range is caused by partial filling of hole traps by positive charge generated by high-field tunnel injection of electrons and by acceleration of degradation processes in the gate dielectric occurring because of high-field injection. The annihilation of a fraction of positive charge and injected electrons, as it has been shown in Andreev et al [27] and Andreev et al [28], can result in rising of amount of surface states at the Si/SiO2 interface, and it can accelerate degradation processes cause by restructuring of the interface and the dielectric film.…”

“…Under the mode, electric fields in the dielectric film significantly increase and these stimulate the accumulation of higher values of positive charge at the same radiation dose. However, when the sensor is under the mode, besides charge effects caused by radiation ionization ( Figure 2) and discussed in detail in Schwank et al [24], Fleetwood et al [25], and Oldham et al [26], it is essential to take into consideration the following charge effects [27,28]: additional generation of positive charge as a result of thermalization of injected electrons (Figure 2, process 11), annihilation of a fraction of positive charge caused by interaction with injected electrons (Figure 2, process 8), generation of additional surface states which takes place because of annihilation of a positive charge fraction and injected electrons ( Figure 2, process 9). In accordance with the model suggested in Andreev et al [27] and Andreev et al [28], we use the following set of equations to describe sensor functioning when it is under concurrent influence of ionizing radiation and high-field injection of electrons:…”

“…Sensors 2020, 20, 2382 4 of 11 -in order to calculate current density initiated by ionization radiation we apply the following equation [24,27,28]:…”

“…Thus, utilization of the MOS sensors under the mode of high-field injection of charge into the dielectric requires the additional analysis of charge effects taking place in the dielectric film and it is required to take influence of these effects into consideration when processing experimental data and choosing operation modes of the sensors [27,28]. For this analysis one can use the model, suggested in the paper, taking into consideration parameters specific to sensors chosen.…”