Submicrometer transmission mask fabricated by low-temperature SF6/O2 reactive ion etching and focused ion beam

A novel technique is presented to fabricate a silicon submicrometer transmission mask for nanofabrication. One of the applications of the mask is to fabricate a single electron transistor using an ultrahigh vacuum scanning tunneling microscope. The mask fabrication processes involve KOH wet etching, electron beam lithography, low-temperature SF6/O2 plasma-assisted reactive ion etching and focused ion beam techniques. Using this method, we fabricated masks with pattern sizes of 2.5×2.5 mm2 and opaque parts of submicrometer scale. After the evaporation, by using the mask a submicrometer gap on the metal pattern can be obtained.