Height control of silicon nano-whiskers embedded in ultra thin silicon nitride layers by rapid thermal annealing

Two steps are necessary to produce nanometre sized silicon whiskers rising out of ultra thin silicon nitride layers: (i) production of under-stoichiom etric silicon nitride surface layers by ion implanting of silicon wafer mat erial, (ii) growth of silicon whiskers by the formation of silicon nitride bonds in the surface region through rapid thermal electron beam annealing. Depending on the implantation and annealing conditions, whiskers of differe nt height and width can be produced. As an example, 25 nm high whiskers wer e formed by implanting 10 keV N-15(2)+ ions into silicon (fluence 5 x 10(16 ) cm(-2)) followed by rapid thermal electron beam annealing at 900 degreesC for 15 s. In atomic force microscope studies, it was observed that the str uctures became more pronounced with increased temperature. Resonant nuclear reaction analysis revealed the absence of nitrogen in the whiskers and the stoichiometry of the silicon nitride layer formed by implantation. (C) 200 1 Elsevier Science B.V. All rights reserved.