Nanometer-scale Ge selective growth on Si(001) using ultrathin SiO 2 film

Abstract

We performed nanometer-scale Ge selective growth using ultrathin silicon dioxide film on Si(001) surfaces. Growth was observed in real time by scanning tunneling microscopy (STM). Window areas with a size of 10–50 nm were fabricated using two different methods: void formation during thermal decomposition of the oxide and field-emission electron-beam irradiation from an STM tip. Selective epitaxial growth was achieved by introducing germane gas (GeH 4). With the first method, 3D nucleations occurred near the periphery of the voids and several Ge clusters of irregular shape grew. With the second method, 3D nucleations occurred at the center of the window, and several clusters coalesced forming one hut cluster. The second method was used to form a nanometer-scale Ge dot array.