Investigations on the Formation of SiO₂in Si⁺-Implanted Al₂O₃

We measured Raman spectra of Si + -implanted Al 2 O 3 at room temperature before and after annealing in vacuum. It is found that SiO 2 is formed even before annealing and the Raman band attributed to the network Si-O-Si symmetric-stretching vibration mode grows with annealing between 300°C and 500°C. It is also found that Al atoms are emitted from the surface of Al 2 O 3 with annealing above 900°C. In forming SiO 2 in the surface layer of Al 2 O 3 , implanted Si atoms obtain oxygen atoms from Al 2 O 3 by breaking Al-O-Al bonds. We discuss the chemical reactions of implanted Si atoms with Al 2 O 3 induced by ion implantation and subsequent thermal annealing.