The Transient Response of Transistors and Diodes to Ionizing Radiation

Mathematical models describing the response of diodes and transistors to ionizing radiation are derived from the continuity and diffusion equations and, in the case of the transistor, the charge control model. Solutions are obtained for both steady-state and transient radiation environments. In addition to being of use in understanding device behavior, these solutions also indicate those device parameters which must be optimized to reduce transient response and therefore provide criteria for the design and/or selection of devices with minimum response. A model is also presented which describes the nonlinear effect of collector multiplication upon the collector photocurrent of a transistor. This model is used as a basis for explaining and predicting the nonlinear relation between the peak photo-response and the radiation dose which has been observed in some devices.