Fabrication and characterization of diamond-clad silicon field emitter arrays

Microsized silicon tip arrays with sharp curvature were formed based on the techniques including reactive ion etching and oxidation-sbarpening. A new fabrication technology of polycrystalline diamond-clad Si microtips using microwave plasma CVD(MPCVD) was subsequently developed to improve the capability and stability of the field emission from the pure Si tips. By means of SEM and transmission electron microscopy (TEM), the as-deposited films are found to be polycrystalline diamond with fine grain (similar to 800 Angstrom) structure. With the anode voltage of 1100V and anode-to-cathode distance of 30 mu m, the emission current of 240 mu A in a 50 x 50 diamond-clad Si microtip array can be achieved, which is much higher than those for Cr-clad and pure Si microtip arrays. Based on curve fitting of a Fowler-Nordheim (F-N) plot, such great improvement is partially attributed to the lowering of the effective work function from 5.5 eV to 2.08 eV.