Nanometer-scale Ge selective growth on Si(001) using ultrathin SiO2 film

We performed nanometer-scale Ge selective growth using ultrathin silicon di oxide film on Si(001) surfaces. Growth was observed in real time by scannin g tunneling microscopy (STM). Window areas with a size of 10-50 nm were fab ricated using two different methods: void formation during thermal decompos ition of the oxide and field-emission electron-beam irradiation from an STM tip. Selective epitaxial growth was achieved by introducing germane gas (G eH4). With the first method, 3D nucleations occurred near the periphery of the voids and several Ce clusters of irregular shape grew. With the second method, 3D nucleations occurred at the center of the window, and several cl usters coalesced forming one hut cluster. The second method was used to for m a nanometer-scale Ge dot array. (C) 2000 Elsevier Science B.V, All rights reserved.