Reliability in MOS integrated circuits

The reliability of state-of-the-art MOS Technology is dominated by trading off one failure mechanism versus another. The traditional predominant failure mechanism of oxide breakdown has moved into a new era where screening of defect related infant mortality failures can impinge or oxide wearout. It is shown that these predicaments were inevitable as a consequence of the continued scaling of device feature sizes. Scaling has had perhaps its largest impact on wearout type failure mechanisms, where for example: lifetime due to hot electron degradation has an exponential dependence on scale factor, and metal and contact electromigration lifetime can be reduced by as much as the 7th and 9th powers of the scale factor respectively. Random soft error failure rates can also depend exponentially on scale factor. The following tradeoffs on technology parameters are analyzed: soft error and oxide hard failures vs oxide thickness, hot electron degradation and soft errors vs supply voltage, and moisture and, electromigration resistance vs isolation PSG layer phosphorus concentration.