Visible photoluminescence from Tb3+ ions implanted into a SiO2 film on Si at room temperature

Visible photoluminescence (PL) from Tb³⁺ ions in SiO ₂ has been investigated at room temperature. The Tb ions were implanted into a 200 nm thick SiO₂ layer on a Si wafer. Since the PL of rare-earth ions is sensitive to their concentration, a uniform depth profile of Tb ions is important for reliable results. To achieve it, multiple implantations were conducted at 50, 100, 190 keV to a total dose of 8.8×10¹⁴-1.3×10¹⁶ ions/cm². The PL spectrum consists of sharp lines due to 4f-4f transitions of Tb³⁺ ions and a broad band due to defects of SiO₂. The PL lines from the ⁵D₄ level of Tb³⁺ increase superlinearly with Tb concentration up to 1 at%. and are dominant over the defect band. The residual defect band is reduced by H₂/N₂ annealing at 900°C. Then the defect-free PL from Tb:SiO₂ is attained