Track 1 Session 5
9:10 to 10:10 a.m. Thursday March 26, 2009

Reliability Evaluation Using Step-Stress Testing Under Changing Degradation Conditions

Ramp stress testing is a widely used technique for reliability assessment. Dependent on sample size, stress profile and data accuracy, various techniques in different forms exist which also extract long-term reliability parameters from these short-term stress tests. To save time, high stress levels are applied to the device under investigation. As the mechanism of degradation changes with the stress values exceeding a certain threshold, a natural limit is set. It would be of great benefit to test at higher levels to compensate for unwanted second order effects. This presentation will guide through an example and explain how a natural changing degradation mechanism can be compensated for accurate reliability evaluation.

Key Words: Step-Stress Testing, Time Varying Stress, V-Ramp, Compensation of Changing Degradation Mechanisms, fWLR, Gate Oxide Reliability, Cumulative Exposure Model, Modified Stress-Profile

Andreas Aal
ELMOS Semiconductor AG
Germany