Two Layer Surface Exfoliation on Si 3 N 4 /Si by Sequential Implantation of He and H Ions

n -Type Si(100) wafers with a thermally grown Si 3 N 4 layer (∼170 nm) were sequentially implanted with 160 keV He ions at a dose of 5 × 10 16 cm −2 and 110 keV H ions at a dose of 1 × 10 16 cm −2 . Depending on the annealing temperature, surface exfoliations of two layers were observed by optical microscopy and atomic force microscopy. The first layer exfoliation was found to correspond to the top Si 3 N 4 layer, which was produced at lower annealing temperatures. The other was ascribed to the implanted Si layer, which was formed at higher temperatures. The possible exfoliation processes are tentatively discussed, and potential applications of such phenomena are also suggested.