Quality Improvement of SiO_2-Films by Adding Foreign Gases in Photo-Chemical Vapor Deposition

摘要

We have developed a new scheme for SiO_2 film preparation in which tetraethoxyorthosilicate (TEOS: Si(OC_2H_5)_4) is photo-dissociated by vacuum ultraviolet Xe_2 excimer radiation (λ=172 nm) at room temperature. The SiO_2 films include impurities of C and H atoms and/or molecules. We have tried to avoid impurity inclusion by adding foreign gases to TEOS. Addition of O_2 molecules results in decrease of C-H impurity inclusion and also improvement in gap filling characteristics. O-H impurity increases by adding O_2 molecules is possibly removed by curing the films around 200°C.