Interface engineering of photoelectrochemically prepared Si surfaces

The oxide of Si(1 1 1) formed by electropolishing in dilute ammonium fluoride solution is analysed by photoelectron spectroscopy using synchrotron radiation. The oxidic layer is about 3.1 nm thick and contains Si-F_x species as well as oxyfluorides. The oxyfluorides are found preferentially at the electropolishing layer surface. SiOH species are concentrated at the oxidic film/substrate interface. The full width half maximum of the Si 2p line indicates that the Si/electropolishing oxide interface is smoother than the Si/natural oxide interface.