Data for Implementation of MeV heavy-ion implantation into a microstructures with a defined pattern structure using a nuclear microprobe

1. Sample preparation Microscope Slides (25 × 75 × 1 mm) from Knittel Glass were used as a substrates to better visualize the processes occurring at each stage due to their transparency. Slides were cut into three parts to obtain square samples with a side length of 25 mm. Poly(methyl methacrylate) (PMMA) was used as the resist material. PMMA powder was dissolved in acetone at a weight ratio 1:8. It was then spin-coated onto the substrate at 2500 rpm for 120 s, resulting in a 10 μm thick PMMA film on the glass. 2. Fabrication of PMMA mask Proton beam writing was performed using a microprobe chamber in our laboratory. A 2 MeV proton beam, focused to a spot of 1.3 × 4.0 µm2 at a beam current of 180 pA was used for direct ion beam lithography. Although the optimal dose for MeV proton beam writing in PMMA is considered to be in the range of 80–150 nC/mm2, in this work we used 160 nC/mm2 (1 × 1014 protons/cm2). This value was determined to be optimal for our setup based on our prior internal research. The same research also showed that the best results were obtained by performing the irradiation not in a single scan but in 10 consecutive loops, which was chosen to reduce the radiation-induced heating effect and the influence of beam current fluctuation. After irradiation, the development of microstructures was carried out using conventional dip development in a 3:7 water/isopropanol (IPA) solution (volume ratio). 3. Heavy ion implantation Implantation of heavy ions was carried out in the implantation chamber in our laboratory. Gold ions with an energy of 2.5 MeV were used for better visualization of the implanted area. Irradiation was performed in raster scanning mode using an electrostatic scanning system. The beam current was monitored throughout the entire irradiation, the beam current density was 25nA/cm2 and the accumulated dose was 1 × 1015 at/cm2. 4. Mask removing The final step in the creating of the material with heavy ions implanted in the desired pattern is the removal of the resist mask. This is achieved by subjecting the sample to acetone until the mask is fully dissolved. The sample has thus been prepared for utilisation in the intended application.