Surface barrier detection in plasma‐enhanced chemical vapor deposition oxides

The performance standards of plasma‐enhanced chemical vapor deposition (PECVD) oxides increase as device sizes shrink and densities increase for ULSI. Future PECVD dielectric quality may be compromised by the effects of contaminants and/or charged ionic species that are present in the gaseous ambient which the wafers are exposed to. As a result of being left at the oxide/silicon interface, these gaseous ambient defects such as metallic ions can adversely effect reliability and performance. Moreover different types of PECVD oxides require different deposition chemistries and are grown to differing thicknesses making it difficult to apply a single C–V test. In this article, the problem is addressed by detecting, nondestructively, such residual interfacial charge postprocessing on product wafers rather than the traditional test wafers. For the first time the effects of mobile ions and interface states at the oxide/silicon interface and in the as‐processed films for various PECVD oxides will be shown using no...