Fe离子注入Al_2O_3陶瓷改变其表面电阻率的研究

Study of Surface Resistivity Modification in Al_2O_3 Ceramics by Fe^(2+) ions Implantation

本文研究了Fe离子注入Al_2O_3陶瓷的注入射程、纵向浓度分布和注入层结构,测定了注入层中的载流子浓度和迁移率,讨论了Al_2O_3陶瓷注入Fe离子其表面层的导电机理。其结论是:注入的Fe^(2-)离子进入Al_2O_3晶格,替代了Al^(3-)离子形成替位杂质。这样注入离子与原有晶格比较呈现一个有效负电荷,形成负电中心。它可以把一个空穴束缚在它的周围,在禁带引入受主能级。

Rutherford backscattering techniqe, Auger electron spectra and X-ray electron spectra are utilized to study the implanted ion range,the ion concentration as a function of distance from the free surface and the structure of implanted films. The carrier concentration and mobility are determined by Van der Pauw method. Finally, the film conduct mechanism is discussed briefly. We conclude that implanted Fe^(2+) ions get into the crystal lattice,replacing Al3+ ions and forming vacancies. Some implanted Fe^(2+) stop in the interstitial position. Both point defects form positive charge center and negative charge center in crystal lattice and draw donor level and acceptor level into restricted band. The sample is electron activation.