Very simple method of flattening Si(111) surface at an atomic level using oxygen-free water

Si(111) surfaces were found to be very easily flattened at an atomic level by immersing the wafers in water, from which dissolved oxygen was removed by the addition of sulfite ion as chemical deoxygenator, at room temperature. After the treatment with this oxygen-free water, the Si(111) surfaces slightly misoriented in the 〈112̄〉 direction showed straight and parallel steps and wide terraces under atomic force microscopy observation. When wafers slightly misoriented in the opposite direction were treated in the same manner, the steps showed a characteristic zigzag pattern with an angle of 60°. The steps that appeared on both surfaces were attributable to monohydride steps generated on the edge of flat terraces.