Silicon field emission arrays coated with CNx thin films

Arrays of silicon micro-tips were made by etching the p-type (1 0 0) silicon wafers which had SiO2 masks with alkaline solution. The density of the micro-tips is 2×104 cm−2. The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly. The CNx thin film, with the thickness of 1.27 μm was deposited on the silicon micro-tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X-ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5%, N: 12.6% and O: 17.9%. The silicon arrays coated with CNx thin films had shown a good field emission characterization. The emission current intensity reached 3.2 mA/cm2 at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CNx thin films are likely to be good field emission cathode. The preparation and the characterization of the samples were discussed in detail.