Nanofabrication of tungsten supertip by electron-beam-induced deposition

Two methods were used to fabricate tungsten supertips by electron-beam-induced deposition using 200 keV electrons. The first method is stationary deposition of self-standing tips. The smallest lateral size is less than 10 nm with a rather low aspect ratio of tip. High aspect ratio (up to 30) can only be obtained at a big lateral size with a saturated root diameter of 60-65 nm. The other method is scan deposition of self-supporting tip, with a root width of 7-10 nm and a sharp apex in size of 3 nm. Using this method a higher aspect ratio (more than 72) can be achieved at a smaller lateral size, which is better to fabricate fine supertips for usage.