The influence of elevated temperature on degradation and lifetime prediction of thin silicon-dioxide films

The reliability of gate oxide is a crucial aspect of device downscaling, In this paper, we demonstrate that increasing operating temperature of downsc aled logic devices combined with the increased detrimental effect of elevat ed temperature on very thin SiO2 films will significantly reduce the device reliability. We discuss the effect of elevated temperature on the factors contributing to oxide breakdown and observe that their combined effect does not result in Arrhenius-like decrease of time-to-breakdown. This is relate d to our observation that oxide defects created at different temperatures a re not completely equivalent. Consequently, oxide damage created during ele ctrical stress at different temperatures is not simply cumulative. We also discuss several possible microscopic models attempting to explain this obse rvation. Finally, we briefly review the methodology of the oxide reliabilit y prediction and present a reliability projection for very thin oxides at t he expected elevated operating temperatures.