Ag/Bi_4Ti_3O_(12)/p-Si异质结的制备及其CV特性研究

Fabrication and C-V Characteristics of Ag/Bi_4Ti_3O_(12) /p-Si Heterostructure

为制备符合铁电存储器件要求的高质量铁电薄膜 ,采用溶胶 凝胶 (Sol Gel)工艺 ,制备了Si基Bi4 Ti3O1 2铁电薄膜及MFS结构的Ag/Bi4 Ti3O1 2 /P Si异质结 ,对Bi4 Ti3O1 2 薄膜的相结构特征及异质结的C V特性进行了测试与分析。XRD图谱显示 ,Si基Bi4 Ti3O1 2 薄膜具有沿c 轴择优取向生长的趋势 ,而Ag/Bi4 Ti3O1 2 /p Si异质结顺时针回滞的C V特性曲线则表明 ,该异质结可实现电极化存储。此外 ,对该异质结C V特性曲线的非对称及向负偏压方向偏移的产生原因也进行了分析。在此基础上 ,为提高铁电薄膜的铁电性能及改善其C V特性提出了合理的结构设想。

In order to fabricate high quality ferroelectric thin films qualified for ferroelectric memories, Bi 4Ti 3O 12 ferroelectric thin film on Si substrate and Ag/Bi 4Ti 3O 12 /p-Si heterostructures with the structures of MFS, were deposited by using the Sol-Gel technique. The phase structure of Bi 4Ti 3O 12 on Si and the C-V characteristics hysteresis loops of Ag/Bi 4Ti 3O 12 /p-Si heterostructures were tested and studied detailedly. The XRD patterns of Bi 4Ti 3O 12 thin films showed that the Bi 4Ti 3O 12 thin films preferred orientation in the (001) direction on bare p-Si substrates. The C-V hysteresis curves with clockwise loops proved that the Ag/Bi 4Ti 3O 12 /p-Si heterostructure can realized a memory effect due to the ferroelectric polarization of Bi 4Ti 3O 12 films. In addition, the primary factors having effect on the asymmetry and the shift to negative in C-V characteristics hysteresis loops were put forward. Based on the above results, practicable thoughts to improve the ferroelectric properties and the C-V characteristics of ferroelectric thin films were presented.