Atomic bonding state of silicon oxide anodized in extremely diluted hydrofluoric solution

Recently, silicon (Si) oxide films have been widely used as insulating materials in electronic devices. The bonding states of these films affect the characteristics of each device. Therefore, it is necessary to control the bonding states in these films. In this study, Si oxide films were prepared by anodizing the surfaces of Si substrates using an extremely diluted hydrofluoric (HF) solution. The atomic bonding states of Si oxide films were evaluated using X-ray photoelectron spectroscopy. Si2p peaks of the films were found within the 104 -105 eV range. Simultaneously, fluorine (F)1s spectra were observed. Furthermore, Si-F and/or Si-O-F bonds were created in the film. From depth profiles of atomic content, oxygen (O) was most present on the outermost surface of the film, and F was most present in the layer slightly below the outermost surface. These findings suggest that oxygen and fluorine have different compounding mechanisms in the film respectively. (author)