Study on surface swelling of SiC by high-dose He-ion implantation

Surface modification of hard materials caused by implanting high-concentration He-ion is interesting since it may be applicable to their micro fabrication process. Implantation of He-ion with energies of 140 keV, 570 keV and 1.7 MeV to CVD-polycrystalline β-SiC was carried out to fluences from 1.4×10²⁰ to 1.9×10²² ions/m² using a grid mesh to study possibility of transcription of the grid mesh pattern to SiC. Irradiation temperature was about 300 to 400 K. Masking with 251 μm grid mesh was used. After irradiation, swelling of implanted area was estimated by step-height method using a laser microscope. It was revealed that a mesh pattern was printed on the specimen surface by helium ion irradiation. Relatively large swelling was produced compared with those in other irradiation conditions in the fluence range greater than a few dpa. The height of upheave pattern depended on the implanted He-ion fluence. Implanted energy dependence of the height was small in this experimental conditions. Transcribed pattern on SiC surface was stable after annealing up to 1200 °C when implanted fluence was relatively low (1.8×10² ions/m²).