Analysis of the Behavior of Integrated Schottky Logic in Neutron, Total Dose and Dose Rate Environments

ISL devices were irradiated in neutron, total dose and dose rate environments and their response was explained in terms of (1) circuit configurations, (2) SPICE (nonlinear circuit simulation program) transistor models fitted through experimental data, and (3) physical parameter transistor models based on nominal doping profiles. Three new modelling techniques were developed: (1) determination of SPICE transistor model parameters by a method which allows both low and high injection effects to be present over the current range of interest and does not require graphical analysis; (2) determination of the minority carrier lifetime which characterizes a dose rate upset mechanism and the corresponding lowest steady state dose rate at which upset would occur; and (3) prediction of the primary photocurrent of a transistor neutral region from its saturation current, which can be obtained either from physical model calculations or from properly determined SPICE parameters.