Quality assessment of thin oxides using constant and ramped stress measurements

Two methods are proposed for obtaining extrinsic oxide lifetime data using fast ramped tests. It is shown that the intersection point between the extrinsic and intrinsic branches of a Weibull plot coincides for ramped and constant stress tests. This is the basis of our fast qualification approach, where intrinsic data are obtained by constant voltage stress and extrinsic data are cumulated with a fast ramped test. The correctness of our approaches is supported by constant voltage and exponentially ramped current measurements.