离子注入Zn的Si(001)基片热氧化制备纳米ZnO团簇及其生长行为研究

采用离子注入技术将Zn离子注入Si（001）基片，并在大气环境下加热氧化制备了ZnO纳米团簇.利用电子探针、薄膜X射线衍射仪、原子力显微镜和透射电子显微镜，对注入和热氧化后的薄膜成分、表面形貌和微观结构进行表征，探讨了热氧化温度以及注入剂量对纳米ZnO团簇的成核过程及生长行为的影响.结果表明，Zn离子注入到Si基片表面后形成了Zn纳米团簇，热氧化过程中Zn离子向表面扩散，在表面SiO₂非晶层和Si基片多晶区的界面处形成纳米团簇.热氧化温度是影响ZnO纳米团簇结晶质量的一个重要参数.随着热氧化温度的升高，金属Zn的衍射峰强度逐渐变弱并消失，而ZnO的（101）衍射峰强度逐渐增强.当热氧化温度高于800 ℃以后，ZnO与SiO₂之间开始发生化学反应形成Zn₂SiO₄. 关键词： ZnO纳米团簇 离子注入 微观结构 形貌分析

Growth behavior of ZnO nanoparticles formed on Zn implanted Si(001) combined with thermal oxidation

Si（001） chips were implanted by Zn ions of 40 keV with different ion dosages and are annealed in air at different temperatures. Atomic force microcopy， transmission electron microcopy， X-ray diffraction and electron probe are applied to study the microstructure， morphology and chemical composition of the chips, either as-implanted or annealed at different temperatures. It was found that the as-implanted Zn atoms aggregate into clusters scattering about 35 nm beneath the surface of the chips. During the annealing process， Zn atoms are found to migrate towards the surface of the chips and aggregate into nanoparticles at the interface between the amorphous SiO₂ layer and polycrystal line Si layer. Annealing temperature was found to be the crucial factor controlling the formation of ZnO nanoparticles. ZnO nanoparticles begin to appear at about 400 ℃ and the diffraction intensity of ZnO becomes strong while the diffraction intensity of metallic Zn weakens with increasing annealing temperature. At the annealing temperature of 800 ℃， Zn₂SiO₄ phase was observed due to the reaction between ZnO and SiO₂ or Si.