AVS 46th International Symposium
    Flat Panel Displays Topical Conference Monday Sessions
       Session FP+VT-MoM

Paper FP+VT-MoM9
Fabrication of Aligned High-density Diamond Needles by Dry Etching of Diamond Substrates

Monday, October 25, 1999, 11:00 am, Room 604

Session: Field Emission Displays and Vacuum Packaging Issues
Presenter: D. Jeon, Myong Ji University, Korea
Authors: E.S. Baik, Myong Ji University, Korea
Y.J. Baik, Korea Institute of Science and Technology, Korea
D. Jeon, Myong Ji University, Korea
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Densely packed diamond needles aligned in the same direction are formed by air plasma etching of diamond substrates. Diamond substrates were coated with a thin layer of Mo and then etched by RF or DC plasma with the substrate biased at negative several hundred volts. The shape and the density of the diamond needles could be reproducibly controlled with the etching parameters such as the substrate temperature, pressure, bias voltage, power, and the amount of Mo. If the substrate temperature was high, for example, the needles became thick. Mo acted as an etch-resistant mask for the needle formation. Mo was sometimes self-supplied by the sputtering of the Mo substrate holder during the etching, but the uniformity of the needles could be best controlled by coating small amount of Mo before etching. If the amount of Mo or the pressure was not adequate, the needles did not form or formed only along the edge of the diamond grains. With the optimum condition, we could fabricate sharp diamond needles whose pillar diameter and height were 0.1 µm and 3 µm, respectively. The density was 30 needles/µm@super 2@. Since the needles were highly aligned and always formed in parallel with the field, the direction of the needles could be chosen by tilting the substrate. Not only the polycrystalline diamond films but also the high pressure/high temperature diamond and the natural diamond could be etched to form needles. Our diamond needles can be utilized as the field emission cathode tips, diamond fiber for composite materials, highly efficient heat sinks for their large surface area, and sensors.