Field Acceleration Model for TDDB: Still a Valid Tool to Study the Reliability of Thick SiO2-Based Dielectric Layers?

The aim of this paper is to investigate the reliability of thick oxides that are dedicated to the power integrated device fabrication. The field dependence of defect-related time-dependent dielectric breakdown (TDDB) mode over a wide range of oxide thickness T_OX and electric field E, using multiple wafer fabrication lots, is investigated. TDDB tests are conducted under constant current injection using structures with different areas. For that, we have applied a new electric field model based on a 1/E model (reciprocal field dependence) that is proposed recently in the literature. We show that when the dielectric thickness increases, this electric field acceleration model gives an erroneous prediction of the long-term reliability. We conclude that it is too early to give a generalized law of dielectric to predict their reliability without taking into account the influence of thicknesses. Consequently, the 1/E model may therefore have to be revised.