Nitridation and subsequent oxidation process of Sit11 1) and (100) surfaces for high-density Si pillar formation

For high-density nanometer-scale Si pillar formation, sub-monolayer nitridation of Si (silicon nitride nucleation) in vacuum and subsequent oxidation also in vacuum have been studied for Si (Ill) and (100) surfaces by scanning tunneling microscopy and X-ray photoelectron spectroscopy. It was found that small silicon nitride islands have strong immunity against oxidation and work as oxidation masks for both surfaces, resulting Si pillars with a nitride layer on top. The density and lateral size of Si pillars are primarily determined by nitridation temperature i.e. a higher density is obtained by decreasing nitridation temperature. Furthermore, we have found that the mask effect of the nitrides is sustained even during conventional oxidation in a furnace.