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

Surface modification of hard materials caused by implanting high-concentration He-ions is interesting since it may be applicable to their micro fabrication process. Implantation of He-ions with energies of 140 keV, 570 keV and 1.7 MeV in CVD-polycrystalline β-SiC was carried out at fluences from 1.4×10²⁰ to 1.9×10 ²² ions/m² using a grid mesh to study the possibility of transcription of the grid mesh pattern to SiC. Irradiation temperature was about 300 to 400 K. Masking with a 25 μm grid mesh was used. After irradiation, swelling of the implanted area was estimated by the 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 upheaval pattern depended on the implanted He-ion fluence. Implanted energy dependence of the height was small for these experimental conditions. The transcribed pattern on the SiC surface was stable after annealing up to 1200°C when the implanted fluence was relatively low (1.8×10²¹ ions/m²)