Dielectric property of Ion Beam Enhanced Deposited lithium tantalate thin film infrared detector

Abstract

The Ion Beam Enhanced Deposited (IBED) LiTaO3 thin film infrared detectors with Al/LiTaO3/Pt structure were prepared on the Pt/Ti/SiO2/Si(100) substrate. The crystallization, the film thickness, the dielectric properties, the leakage current and the anti-breakdown ability of the IBED LiTaO3 thin film infrared detector samples were investigated by the different annealing processes. The XRD measured results show that, the prepared samples have the polycrystal structure of LiTaO3 with the preferred orientation of <012> and <104> located at the 2theta of 23.6° and 32.7° respectively. The residual Ta2O5 has been existed in the prepared samples owe to the Li volatilization during the high temperature annealing process. The obtained 587nm thick IBED LiTaO3 thin film infrared detector sample annealed at 550°C has the dielectric permittivity of 39.44, the low dielectric loss of 0.045 at the tested frequency of 100 kHz, and the small current leakage of 4.76×10⁻⁸A/cm² when subjected to the tested electrical field of 400kV/cm. The electrical breakdown experimental results show that the prepared detector samples have strong ability of anti-breakdown and can be subjected to the stronggest electrical field of 680kV/cm. The experimental results show that, the dielectric loss and the leakage current of the IBED LiTaO3 thin film infrared detectors are better than those of the Sol-Gel derived LiTaO3 thin film infrared detectors.