Laser irradiation effects in Si+-implanted SiO2

Abstract Shimizu. Itoh. Matsunami and Fujita have reported experimental results on fused SiO 2 which was implanted with Si + and then either laser or furnace annealed. In view of the importance of this work to the laser processing of SiO 2 , we here present a physically consistent interpretation of what was found. Considering the laser annealings, the shift of the profiles towards the surface , as well as the detailed shapes of the profiles, can be understood in terms of the Soret effect. Re-emission of Si from the surface suggests a role for the well known reaction Si (1) + SiO 2 (1) = 2 SiO ( g ). Considering the furnace annealings the outstanding result is the shift of the profiles away from the surface combined with a persisting re-emission of Si. By analogy with results of Arnold and Peercy for Li-bombarded fused SiO 2 and of Matzke for Xe-bombarded α-quartz. we suggest a role for bombardment-induced nucleation followed by crystal growth during the annealing. This causes the Si impurity atoms to be dragged in part towards the surface and the reaction Si (1) + SiO 2 (1) = 2 SiO ( g ) again to play a role. At the same time the remaining Si impurity atoms are found at a greater depth.