Suspended nanostructures grown by electron beam-induced deposition of Pt and TEOS precursors

Suspended nanostructures (SNSs) are grown by electron beam-induced deposition (EBID) of Pt and tetra-ethyl-ortho-silicate (TEOS) gas precursors on nanopillar tips, by lateral shifting of a scanning electron microscope beam. Shape evolution of SNSs is characterized as a function of electron energy (5, 10, 15 keV) and electron charge deposited per unit length (CDL, 1-9 pC nm-1 range) along the beam track. Pt SNSs grow as single nanowires, evolving from thin (15-20 nm) and horizontal to thick (up to 70 nm) and inclined (up to 60 deg ) geometry as CDL increases. TEOS SNSs consist of multiple nanowires arranged in a stack: horizontal and parallel along the beam shift direction and aligned on top of each other along the beam incidence axis. As the CDL increases, the number of nanowires increases and the top edge of the stack progressively inclines, taking the form of a hand-fan. Deposition yield and overall size of SNSs are found to be proportional to CDL and inversely proportional to electron energy for both Pt and TEOS precursors. As an example of 3D nanoarchitectures achievable by this lateral EBID approach, a 'nano-windmill' TEOS structure is presented.