Papers by Keyword: Poly-SiC

Abstract: We report on experimental explorations of using focused ion beam (FIB) nanomachining of different types of silicon carbide (SiC) thin membranes, for making robust, high-quality stencil masks for new emerging options of nanoscale patterning. Using thin films and membranes in polycrystalline SiC (poly-SiC), 3C-SiC, and amorphous SiC (a-SiC) with thicknesses in the range of t~250nm−1.6μm, we have prototyped a series of stencil masks, with nanoscale features routinely down to ~100nm.

Abstract: A polycrystalline silicon carbide (poly-SiC) surface-micromachined capacitive accelerometer is designed, fabricated and tested. Leveraging the superior thermo-mechanical and chemical resistance properties of SiC, the device is a first step toward cost-effective implementation of a new class of extreme environment accelerometers, for example for high temperature vibration and shock measurements, even thought this initial work is at room temperature. The accelerometer described herein is designed for a range of 5000 g and a bandwidth of 18 kHz, specifications consistent with commercially available piezoelectric devices for high-level mechanical impact measurements. Test results demonstrate the sensor achieving a resolution of 350 mg/√Hz at 1kHz with a sensitivity of 12 μV/g and a bandwidth of 10 kHz at room temperature.

Abstract: This paper explores polycrystalline 3C-silicon carbide (poly-SiC) deposited by LPCVD for fabricating flexible ribbon cable interconnects for micromachined neural probes. While doped silicon is used currently, we hypothesized that poly-SiC will provide enhanced mechanical robustness due to SiC’s superior mechanical properties. Paralleling prior work in silicon, forty-two different designs were fabricated from nitrogen-doped poly-SiC films deposited by LPCVD at 900°C using dichlorosilane and acetylene as precursors. The different designs were then tested in bending and twisting modes. Curved beams were found to bend nearly 250% more than straight beams before fracture. Longer beams withstood greater bending and twisting due to greater compliance. Longer and narrower beams generally outperformed shorter beams irrespective of design. Also, doped poly-SiC beams had, on average, breaking angles that were greater than those of identical doped silicon beams by ~50% in bending and ~20% in twisting modes. The paper details the designs studied, describes the fabrication process for the test structures and compares/contrasts the testing and simulation results related to the different designs to identify best design practices.