Verification of preoxidation effect on deposition of thin gate-quality silicon oxide films at low temperature by a sputtering-type ECR microwave plasma

We have succeeded in preparing thin Si oxide films having a thickness of 9 nm and a breakdown field greater than 8 MV/cm at low temperatures. These films were prepared by a method of combining plasma preoxidation and subsequent sputter deposition using a sputtering-type ECR plasma system. In this study, the effect of the initial plasma preoxidation process was verified by comparing the structural characteristics of the films with and without this process. The chemical etch rate measurements and X-ray photoelectron spectroscopy suggested that well-controlled film structure in the range of 1.3–3 nm from Si substrates was of primary importance for the high breakdown characteristics of the films prepared with the combined method.