Wet Chemical Etching Process of BST Thin Films for Pyroelectric Infrared Detectors

Abstract

Ba_0.8Sr_0.2TiO₃ (BST) thin films were prepared on Pt/Ti/SiO₂/Si substrates by sol-gel processing. The BST thin films were patterned by wet chemical etching and the electrodes were shaped by lift-off technique. An improved etchant with the volume ratio of HF:HNO₃:H₂O₂:H₂O = 1:25:50:20 was developed for BST films etching. SEM graph shows that the unetched BST thin film is dense, crack-free and pore-free. EDS analyses indicate that Ba, Sr and Ti elements of etched areas are removed completely. XRD and AFM results show that the etchant-induced damage of the etched BST films could be partially recovered by post-annealing treatment.

Keywords:

• Barium strontium titanate(BST)
• sol-gel processing
• lift-off technique
• wet chemical etching
• etchant

Acknowledgments

This work has been supported by the National Natural Science Foundation of china through No.50672022 and the Hubei Province Key Laboratory of Refractories and Ceramics Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory through No.G0701.