Influence of 1 nm-thick structural "strained-layer" near SiO/sub 2//Si interface on sub-4 nm-thick gate oxide reliability

The relationship between the structural property and the electrical characteristics of thin SiO/sub 2/ below 4 nm is investigated. The structural "strained-layer" near SiO/sub 2//Si interface is confirmed to affect strongly the TDDB (time dependent dielectric breakdown) lifetime of the thin gate oxides. The increase of the built-in compressive strain analyzed by the XPS (X-ray photoelectron spectroscopy) based technique is experimentally found to decrease the TDDB lifetime.