| A monolithic processing technique for integrating nm-scale silicon structures with μm-scale released beams is presented. The nanostructures consist of released tips and filaments lying in the plane of the wafer. The filaments have lengths of 2–200 μm and widths and heights of 20–200 nm. A tip is essentially a cantilevered filament with a sharpened end. The diameter at the end of a tip is typically 3–4 nm. These structures are integrated with high-aspect-ratio released μm-scale single-crystal-silcon beams, using a single photolithographic mask and readily-available processing technology. This core process has been integrated into two completely different applications: Scanning transmission electron microscopy (STEM) and microelectromechanical systems (MEMS).; STEM was used to characterize the nanostructures in terms of size, shape, surface cleanliness, and crystal structure. In addition, we performed a detailed electron energy loss spectroscopy (EELS) analysis of the low-energy excitations in the tips. This study revealed a number of nanometer-scale phenomena, including shifts in the heights, widths and energies of the plasmon peaks, as well as a new peak at 5 eV which we are identifying as an interband transition. The experimental results are explained in terms of classical electrodynamics.; With regard to MEMS, we show how to integrate 3-axis micromotors with our nanostructures. Each tip or filament can be mounted on its own micromotor and electrified independently of the motor. Due to the lateral geometry, multiple nanostructures can be formed in close proximity to each other, at arbitrary orientations, allowing us to study their interactions in ways which would be difficult with a vertical tip process. Electrical isolation shows a considerable improvement on previous work, with high yield, TΩ or higher leakage resistance, and small crosstalk capacitance. The complete MEMS process requires only three masks. Several applications of this technology are described, some of which have already been carried out by coworkers. |
