Nanometer-scale Si selective epitaxial growth on Si surface windows in ultrathin oxide films fabricated using scanning tunneling microscopy

Abstract

Using scanning tunneling microscopy (STM), nanometer-scale Si(111) and Si(001) windows in ultrathin SiO2 films are fabricated by electron-beam-induced thermal decomposition. At 450–630 °C, the oxidized Si surfaces are irradiated with a field emission electron beam from a STM tip with an energy of 70–150 eV and a current of 10–50 nA. The smallest window size is about 40 nm. The shape of the Si crystals selectively grown on the Si(001) windows is that of a frustum of a quadrangular pyramid, while that on the Si(111) windows is an (111) oriented two-dimensional island. We discuss the influence of the field emission electrons on the fabrication and the selective growth.