Surface application of metal silicides for improved electrical properties of field-emitter arrays

This paper concerns the positive effects of chromium or titanium silicide coating on the electrical characteristics of micro-tips. The metal-coated silicon micro-tips were prepared by the silicidation process. The surface morphologies and electrical properties of the samples were measured and analyzed. It was found that the application of chromium silicide to silicon field emitters decreases the current fluctuation range to about 50% that of a pure silicon emitter. Both metal-silicide-coated samples exhibited high discharge resistances. In particular, the titanium-silicide-coated sample exhibited a discharge resistance up to an emission current of 30 mu A, which is higher than that of the chromium-silicide-coated sample. A silicon-metal-silicide vacuum-band model is proposed to explain the electrical characteristics. The effect of stabilization can be explained in terms of reduced number of chemically active sites resulting in a silicide-protected and chemically stable layer, hence the higher electrical conductivity of the material.