CHEMICAL-STABILITY OF HBF4-TREATED (100)SI SURFACES

Si(100) surfaces were modified by means, of enhanced RCA procedure wit h ''HBF4-last'' and ''HF-last''. Nulling ellipsometric (NE) and second ary ion mass spectrometric (SIMS) measurements revealed that HBF4-trea ted Si surface is more strongly passivated by hydrogen and fluorine th an HF-treated one: the oxidation rate of the HBF4-treated Si surfaces in air was found to be lower than that of the HF-treate surface. Scann ing tunneling microscope (STM) images of HBF4-cleaned surface after 18 h storage in air were quite stable during observation, scanning could be easily performed over a wide area on every plot we chose.