Gamma Total Dose Effects on ALS Bipolar Oxide Sidewall Isolated Devices

Advances in bi-polar technology that increase device performance through the use of oxide sidewall isolation have revived concerns about total dose radiation effects. Extensive Cobalt 60 tests of Texas Instruments ALS devices were conducted and comparative results of "walled" and "nested" emitter devices are included. It was determined that inversion at the Si-SiO2 interface between the isolation oxide and residual EPI material was the source of IIH leakage. Controls were established to improve gamma total dose tolerance.