BST薄膜的湿法化学刻蚀工艺优化及应用初探

采用sol-gel法在SiO2/Si衬底上制备了Ba0.7Sr0.3TiO3(BST)薄膜.利用湿法化学刻蚀技术对BST薄膜进行图形化.通过实验结果对比,选择HF/HNO3/H2O2/H2O(体积比为1∶20∶50∶20)的混合液作为最佳刻蚀液.扫描电镜(SEM)结果表明,刻蚀后BST薄膜表面干净,无残留物,图形轮廓清晰.原子力显微镜(AFM)和X射线衍射(XRD)结果显示,刻蚀后BST薄膜表面粗糙度增大,结晶性退化.对刻蚀后的薄膜在600℃后退火处理,能要在一定程度上恢复其表面形貌和结晶性.应用优化工艺制备BST薄膜阵列,采用剥离法将Au,Ni/Cr和Pt/Ti电极进行微图形化.最后,成功地制备了Au/Ni/Cr/BST/Pt/Ti/SiO2/Si结构的8×8元的红外探测器阵列.

Processing optimization and basic application of wet chemical etching for BST thin films

Ba0.7Sr0.3TiO3（BST）thin films were prepared on SiO2/Si substrates by Sol-gel processing.The BST thin films were patterned by wet chemical etching.Through experiments,the best feed volume ratio of etchant solution was found to be φ（HF∶HNO3∶H2O2∶H2O）=1∶20∶50∶20.SEM results showed that BST thin films exhibited a smooth surface with no residues and the etching edges were clear.AFM and XRD analysis indicated that the roughness（RMS） of BST thin films became larger and the crystallinity was degenerated.After postannealing treatment at 600 ℃,both the microstructure and crystallinity of the etched BST thin films were partly recovered.The array of BST thin films was obtained by the optimum process.Lift-off technique was selected to pattern Au,Ni/Cr and Pt/Ti electrodes.Finally,Au/Ni/Cr/BST/Pt/Ti/ SiO2/Si infrared detector of 8×8 arrays was successfully fabricated.