射频溅射制备的BST薄膜介电击穿研究

Dielectric breakdown of BST thin films prepared by RF sputtering

采用射频溅射制备BST薄膜,研究了薄膜的介电击穿特性.实验表明,在电压增大到传统击穿电压(电流密度出现瞬时增大时的电压)之前,薄膜性能已被破坏,发现在传统击穿状态之前存在另一个新状态———初始击穿状态.通过测试各状态的J-V(电流密度-电压)、J-T(电流密度-温度)特性分析其导电机理,建立了薄膜结构、漏电性能随电场强度增大而变化的模型.最后提出了确定实际意义上击穿电压的方法.

Dielectric breakdown of BST thin films prepared by RF sputtering is studied in this paper. It is found that, the BST thin films will have already broken before the voltage reaches to conventional breakdown strength, which is normally tested by ramping the voltage and recording the voltage at which an abrupt rise in leakage current is observed. Accordingly, another state of BST thin films, i. e. the incipient breakdown, is found instead. The model which describes the films＇ configuration changes with the increase of voltage is established, and a new method to determine the practical breakdown strength is proposed.