Dose Dependence of Recrystallization Behavior in Germanium-Ion-Implanted Polycrystalline Silicon Films

Recrystallization behavior in polycrystalline silicon (poly-Si) films amorphized by germanium ion (Ge+) implantation on a SiO2 layer is investigated. The nucleation rate decreases as the Ge+ dose increases, which is strongly related to the increase in the disordered states in as-implanted amorphous Si films. The growth rate first increases and then decreases as the Ge+ dose increases, which can be explained by the strain effect induced by Ge atoms. The grain size of recrystallized poly-Si films increases as the Ge+ dose increases. The optimum implantation dose to achieve good crystallinity is found to be 1×1015 ions/cm2.