Patterning silicon carbide on silicon by ion modification of C-60 films

Abstract

Reaction of C-60 with Si at temperatures above 800 degrees C is known to give SiC. Furthermore, treatment of vapor-deposited C-60 films with a beam of Ar+ transforms the surface layer of C-60 into a nonvolatile carbon deposit. Based on these two findings, we have developed a method for patterning SiC structures on silicon. C-60 is first vapor deposited onto a clean Si surface. By rastering the ion beam on selected parts of the sample, we write a chosen pattern on the C-60 film. Upon increasing the temperature to around 300-350 degrees C, the C-60 film remains only in the areas that were subjected to irradiation, while it evaporates off the remaining surface. During the subsequent annealing at 900 degrees C, the modified C-60 layer confines the underlying C-60 On the silicon surface, allowing the formation of SiC. At shorter times, traces of the capping layer are visible at the edges of the irradiated zone. These results demonstrate the principle of fabricating lithographically patterned SiC structures on silicon without masking and etching processes and with the high lateral resolution possible with ion beams.