Total ionizing dose degradation of power bipolar integrated circuit

Variations of ionizing dose response in terms of various types of radiation and bias conditions were presented for voltage regulator produced in "National Semiconductor" bipolar process. Technological realization of monolithic integrated circuit, also as its impact on device's degradation were shown. Manifestations of surface recombination mechanisms in semiconductor and positive charge trapping in oxide were presented. Changes of serial transistor's maximum collector current, collector - emitter dropout voltage, output voltage and load regulation characteristics were presented for voltage regulators from two batches made by the same manufacturer. Examined samples showed severe characteristics degradation even at low and medium total ionizing dose levels, indicating low radiation hardness of "National Semiconductor" bipolar process. Devices from various lots showed significant differences in radiation response.