Wet-chemically passivated silicon interfaces:: Characterization by surface photovoltage measurements, and spectroscopic ellipsometry methods

By combining SPV and SE measurements the density and energetic distribution of interface states were correlated to the morphological structure of the wet-chemically cleaned Si-surfaces. By this systematic investigations, a special Hydrogen-termination procedure was optimized and atomically flat Si (111)-surfaces without any native oxide coverage were obtained, which were characterized by an intrinsic surface state distribution and a very low surface state density D-it,D- min approximate to 1.5 x 10(10) cm(-2) eV(-1). On these surfaces the resonant absorption due to the Si-H bonds was directly observed by infrared ellipsometry using only a single reflection. This FTIR ellipsometry method is capable of routinely sensing the extent of H-termination of standard wafers, By hot water treatment of H-terminated surfaces, thin passivating oxide layers up to a thickness of 25 Angstrom were obtained with a surface state density significantly lower than that of conventionally prepared chemical and thermal oxides.