Dielectric breakdown distributions for void containing silicon substrates

Distributions of gate oxide failure in various types of silicon substrate materials have been investigated for a wide range of oxide thicknesses. Silicon substrates containing various well-characterized void distributions along with defect-free materials were tested using special low-series resistance capacitor structures. Results of both ramped field tests of variable ramp rate and constant field tests were performed and analyzed within the framework of Weibull statistics. Ramped field tests are not “time zero dielectric breakdown” tests as is commonly asserted. They can in fact be very useful in extrapolating time dependent failure. The same set of Weibull parameters can be used to describe both ramped field and constant field wearout tests if an appropriate model for the time dependent damage accumulation during the field ramp is used. There are implications for reliability predication and the burn-in screening of device populations containing such defects.