10th U6+ Consortium of African Universities International Conference

This study examines the effects of post-deposition annealing in oxygen (O2) and nitrogen (N2) atmospheres on the structural and surface properties of RF-sputtered Tb4O7 thin films deposited on silicon (Si). Films annealed at 500 °C were compared with an unannealed reference sample. GIXRD analysis reveals that annealing improves crystallinity and promotes grain growth while preserving the cubic Tb4O7 phase, with crystallite sizes increasing from 10.97 nm (standard) to 17.26 nm (O2-annealed) and 25.86 nm (N2-annealed). FESEM images confirm pronounced grain growth, particularly for the N2-annealed film, which exhibits the largest, most uniform grains and a smooth, void-free surface. AFM results support these observations, showing a reduction in RMS roughness from 1.91 nm (standard) to 1.58 nm (N2) and 0.98 nm (O2). EDX confirms Tb, O, and Si elements, with the N₂-annealed film showing the highest oxygen content. Overall, N2 annealing yields highly uniform, low-defect films suitable for Si-based semiconductor applications.