Mo-Gate MOS Devices Stability Under Long-Term Positive Bias-Temperature Stressing Test

Abstract

To examine Mo-gate devices stability, long-term positive bias-temperature stressing tests were made. Degradation modes, two kinds of negative flat-band voltage shifts and a positive threshold voltage shift originating from surface state generation, and their dependence on device structures, such as Mo film thickness and gate length, were clarified. Device lifetime estimation was made on the basis of dagradation mode analysis and bias-temperature stressing test results. Degradation origin is discussed.