Nanoparticle Formation in Si Implanted with Zinc and Oxygen Ions With Subsequent Annealing in Vacuum

Abstract—

Nanoparticle formation in silicon subsequently doped with Zn and О ions and annealed in vacuum is presented in this paper. Standard n-type Si plates with the (100) orientation, a thickness of 380 nm, and a diameter of 76 mm and grown by the Czochralski method are implanted with ⁶⁴Zn⁺ ions with a dose of 5 × 10¹⁶ cm^–2 and an energy of 50 keV and with ¹⁶О⁺ ions with a dose of 2 × 10¹⁷ cm^–2 and an energy of 20 keV. The ion current does not exceed 0.5 µA/cm² during implantation so that plate overheating in comparison to room temperature does not exceed 50°С. Then the plates were cut into samples with dimensions of 10 × 10 mm and annealed at a temperature of 400 to 900°С with a step of 100°С in vacuum for 30 min. It is discovered that, after implantation, an amorphized layer with a thickness of approximately 150 nm is formed in Si; amorphous Zn and O nanoparticles with dimensions of about 5 nm are formed in it. Radiation-induced defects are annealed during heat treatment, and the amorphized-layer thickness decreases. After annealing, a peak at a wavelength of 370 nm forms at 700°С in the photoluminescence spectrum; it is caused by the formation of ZnO-phase nanoparticles. This peak vanishes after annealing at 900°С, and a peak at a wavelength of 425 nm appears in the photoluminescence spectrum; it is due to the appearance of the Zn₂SiO₄ phase.