The Impact of Interface States on Sub-Threshold Leakage and Power Management in CMOS Devices and Circuits

Abstract

Space applications expose electronic systems to levels of radiation that are damaging to the individual components. Considerable effort has gone into the "hardening" of electronic components against total-dose damage by ionizing radiation. This thesis explores the degree to which commercial-of-the-shelf parts are affected by ionizing radiation. In particular, concentration is on the effect of interface state generation resulting from ionizing radiation on overall device performance. Various sized 0.13μm MOSFET devices were simulated, fabricated, irradiated and tested. Significant increases in the sub-threshold swing and leakage current were observed following a 1MRad total-dose gamma ray irradiation. Subsequently, logic inverter structures exhibited increased sub-threshold swing and total power dissipation following simulations that modeled increasing radiation exposure. Finally, an 11-stage ring oscillator experiment was conducted. A decrease in power for increased irradiations was observed in previous work [49], but without explanation. This work attempts to provide a logical framework for understanding this observation.