Models of charge transport in electron-beam irradiated insulators

Carrier generation in an insulator due to electron-beam irradiation causes a radiation-induced conductivity. This phenomenon can be considered in the equations for charge transport in two different ways: A first, macroscopic, approach takes into account only the radiation-induced conductivity while a second, microscopic, scheme is based on a detailed description of the carrier generation and recombination in the insulator including the carrier mobility. As compared to the macroscopic approach, the microscopic procedure requires a larger and more complicated system of equations and the knowledge of the generation and recombination rates. Therefore, numerical evaluations on the basis of the macroscopic model are often more desirable. In this case, only the knowledge of the radiation-induced conductivity, which is easily measurable, is necessary. Numerical results for open-circuit conditions, obtained from both models, are compared and advantages and drawbacks of the two models discussed.