Characterization of silicon surface preparation processes for advanced gate dielectrics

An overview is given on the issues associated with the surface preparation of silicon surfaces for advanced gate dielectrics and the appearance and nature of the water surface after different chemical treatments. The use of electrochemical open-circuit potential (OCP) measurements as a simple and powerful technique to investigate and characterize wet silicon surface-preparation processes is demonstrated. A method is also introduced that permits the correlation of the measured open circuit potential difference to the thickness of a growing native oxide. The etching behavior of an ultrathin thermally grown silicon oxide layer in hydrofluoric acid (HF) is discussed as a new result obtained using the OCP technique.