Preparation of BST ferroelectric thin film by metal organic decomposition for infrared sensor

摘要

Barium strontium titanate (Ba1-xSrxTiO3) ferroelectric thin films have been prepared by metal organic decomposition (MOD) on Pt/Ti/SiO2/Si and on micromachined wafer with an aim to fabricate dielectric bolometer type infrared (IR) sensor. The XRD pattern and D-Vhysteresis curve of the film have been measured in order to investigate the effects of the final annealing temperature and annealing time on the property of the film. The results show that the films annealed at 700 degreesC or 800 degreesC all have good perovskite structure, while the film annealed at 800 degreesC has better ferroelectric loops. Films annealed at 800 degreesC with different annealing time from 5 to 60 min show a similar perovskite structure, among which films annealed at 30 and 60 min condition have the better ferroelectric loops. Temperature coefficient of dielectric constant (TCD) of the MOD made BST thin film on micromachined substrate is about 1%/K. The uniformity of the BST film on micromachined Si wafer also has been confirmed to be good enough for operation of sensor array. Chopperless operation has been attained and infrared response evaluation of the fabricated sensor also has been carried out with R-v of 0.4 kV/W and D* of 1.0 x 10(8) cm Hz(1/2)/W, respectively. (C) 2003 Elsevier B.V. All rights reserved. [References: 12]