Towards local growth of individual nanowires on 3D microstructures by using a minimally-invasive catalyst templating method

We present a novel minimally invasive post-processing method for catalyst templating based on focused charged particle beam structuring, which enables a localized Vapor-Liquid-Solid (VLS) growth of individual nanowires on pre-fabricated three-dimensional micro- and nanostructures. Gas assisted Focused Electron Beam Induced Deposition (FEBID) was used to deposit a SiOx surface layer of about 10 x 10 micrometer on top of a silicon atomic force microscopy cantilever. Gallium focused ion beam (FIB) milling was used to make a hole through the SiOx layer into the underlying silicon. The hole was locally filled with a gold catalyst via FEBID using either Me2Au(tfac) or Me2Au(acac) as precursor. Subsequent Chemical Vapor Deposition (CVD)-induced VLS growth using a mixture of SiH4 and Ar resulted in individual high quality crystalline nanowires. The process, its yield and the resulting angular distribution / crystal orientation of the silicon nanowires are discussed. The presented combined FIB / FEBID / CVD-VLS process is currently the only proven method, which enables the growth of individual monocrystalline SiNWs on pre-structured substrates and devices.