Development of 400°C operational relaxor ferroelectric based thin-film capacitor with exceptionally high stability
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2015-02-06 |
| Journal | The Japan Society of Applied Physics |
| Authors | Somu Kumaragurubaran |
Abstract
Section titled “Abstract”High-temperature operating electronic devices are indispensable for geothermal, automotive, space and aviation applications. SiC and diamond based transistors and diodes are capable of operating at 500C. In contrary, the capacitors can operate up to 175C only and are bulky too. Therefore, it is necessary to develop monolithic thin-film capacitors that can operate at least up to 400C. In the previous meeting, we demonstrated (1-x)[BaTiO3] xBi(Mg2/3Nb1/3)O3relaxor ferroelectric epitaxial thin-film capacitor that functions up to 400C [1]. However, the high-temperature stability of relative dielectric constant (r) was poor especially, at 25 - 100 C regime. Here, we show the exceptionally-high temperature stability of Ta doped BT-BMN compositionally engineered polycrystalline thin-film stacked capacitor. In the epitaxial capacitor, BT-BMN films were deposited using pulse laser deposition method. A significant out-diffusion of Bi was observed, in x-ray photoelectron spectroscopy analysis, on post-growth annealed BT-BMN surface. This caused the increase of dielectric loss and dielectric constant at high-temperatures that eventually lowered the temperature stability of the capacitor. To suppress the Bi out-diffusion Ta doped (max. 3 mol%) BT-BMN layer was introduced in the film at regular spacing. It significantly suppressed the Bi out-diffusion and improved the temperature stability of r and also the leakage current. However, the dielectric constant was dropped around room temperature. As a counter measure, we altered the composition ratio of BT and BMN film to shift the r peak-maximum towards low temperature region according to the results of bulk ceramics. Figure 1a depicts the compositionally engineered Ta doped BT-BMN film stack. Figure 1b shows the dielectric constant and dielectric loss as a function of temperature. Note that the dielectric constant exceeds 400 and the temperature stability is below 4% in 23-400C range at 50 kHz. [1] S. Kumaragurubaran et al. 75 th JSAP-Fall Annual Meetings, 18p-A9-2 (2014). 第62回応用物理学会春季学術講演会 講演予稿集 (2015 東海大学 湘南キャンパス) 13a-A21-8
Tech Support
Section titled “Tech Support”Original Source
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