Local oxidation induced by inhomogeneous stress on the blistered Si surface

Igarashi, Shinichi*; Itakura, Akiko*; Kitajima, Masahiro*; Nakano, Shinsuke*; Muto, Shunsuke*; Tanabe, Tetsuo*; Yamamoto, Hiroyuki; Hojo, Kiichi

Surface stress can be utilized positively in modifying the surface reaction potential and increasing the surface reactivity. Blister is a local protrusion of solid surface induced by gas ion irradiation, and is considered to create local stress on surface layers. Si(100) substrate was irradiated with 10 keV H (fluence; 110 ions/m) at an angle of 30 to the surface normal. The blisters of several m in diameter at the bottom were formed. After the ion irradiation, the substrate was oxidized. By means of scanning Auger microscopy, we observed that the rims of the blisters have higher oxygen intensities than the flat surfaces and the tops have lower than the flats. The calculated stress distribution of the blister shows that the surface layers should be stretched laterally at the top of blisters and are compressed at the rim, relative to the flat surfaces. The O distribution clearly consists with the stress distribution of the surface. Our results demonstrate a patterned oxidation of Si surface applying its reactivity depending on the surface stress.