Method for cleaning the surface of a silicon substrate using hydrogen fluoride gas and hydrogen chloride gas in hydrogen ambient

To obtain a bare silicon substrate surface, in situ cleaning in hydrogen ambient at atmospheric pressure in a quartz chamber using a combination of hydrogen fluoride gas and hydrogen chloride gas is studied. A native oxide film can be removed by anhydrous hydrogen fluoride gas at room temperature. Hydrogen chloride gas is additionally used to remove organic hydrocarbon film at 973 K. No increase in haze intensity of the surface of the silicon substrate is observed after heating at 1223 K in a hydrogen ambient at atmospheric pressure. Discussion in terms of the pit formation model indicated that native oxide film and organic hydrocarbon film are completely removed from the entire silicon surface by the in situ cleaning method. The chemical reaction of hydrogen fluoride gas at the surface of the silicon substrate is additionally discussed.