Neutron Hardness Assurance for Power Transistors

A method for providing neutron hardness assurance for power transistors based on correlation techniques and the application of a group of screening parameters has been successfully demonstrated. Prediction of power transistor gain and saturation voltage at high currents in neutron environments is complicated because of the combined effects of carrier lifetime degradation and carrier removal in base and collector regions of transistors. Simple base region recombination models are not adequate and a two-region, two-dimensional analytical model describing transistor radiation response at high currents is not yet available. However, statistical techniques can be applied to experimental data obtained on sample devices from a production line to derive equations that correlate device radiation performance with selective nondestructive electrical screening measurements. Hardness assurance of each subsequent part from specific production line is accomplished by applying individual device screening data to the derived equations and evaluating predicted response in accordance with desired performance criteria.