This title appears in the Scientific Report :
2014
Please use the identifier:
http://hdl.handle.net/2128/16804 in citations.
Please use the identifier: http://dx.doi.org/10.1063/1.4891831 in citations.
Impact of composition and crystallization behavior of atomic layer deposited strontium titanate films on the resistive switching of Pt/STO/TiN devices
Impact of composition and crystallization behavior of atomic layer deposited strontium titanate films on the resistive switching of Pt/STO/TiN devices
The resistive switching (RS) properties of strontium titanate (Sr1+xTi1+yO3+(x+2y), STO) based metal-oxide-metal structures prepared from industrial compatible processes have been investigated focusing on the effects of composition, microstructure, and device size. Metastable perovskite STO films we...
Saved in:
Personal Name(s): | Aslam, N. (Corresponding Author) |
---|---|
Longo, V. / Rodenbücher, C. / Roozeboom, F. / Kessels, W. M. M. / Szot, K. / Waser, R. / Hoffmann-Eifert, S. | |
Contributing Institute: |
Elektronische Materialien; PGI-7 |
Published in: | Journal of applied physics, 116 (2014) 6, S. 064503 - |
Imprint: |
Melville, NY
American Institute of Physics
2014
|
DOI: |
10.1063/1.4891831 |
Document Type: |
Journal Article |
Research Program: |
Exploratory materials and phenomena |
Link: |
OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1063/1.4891831 in citations.
The resistive switching (RS) properties of strontium titanate (Sr1+xTi1+yO3+(x+2y), STO) based metal-oxide-metal structures prepared from industrial compatible processes have been investigated focusing on the effects of composition, microstructure, and device size. Metastable perovskite STO films were prepared on Pt-coated Si substrates utilizing plasma-assisted atomic layer deposition (ALD) from cyclopentadienyl-based metal precursors and oxygen plasma at 350 °C, and a subsequent annealing at 600 °C in nitrogen. Films of 15 nm and 12 nm thickness with three different compositions [Sr]/([Sr] + [Ti]) of 0.57 (Sr-rich STO), 0.50 (stoichiometric STO), and 0.46 (Ti-rich STO) were integrated into Pt/STO/TiN crossbar structures with sizes ranging from 100 μm2 to 0.01 μm2. Nano-structural characterizations revealed a clear effect of the composition of the as-deposited STO films on their crystallization behavior and thus on the final microstructures. Local current maps obtained by local-conductivity atomic force microscopy were in good agreement with local changes of the films' microstructures. Correspondingly, also the initial leakage currents of the Pt/STO/TiN devices were affected by the STO compositions and by the films' microstructures. An electroforming process set the Pt/STO/TiN devices into the ON-state, while the forming voltage decreased with increasing initial leakage current. After a RESET process under opposite voltage has been performed, the Pt/STO/TiN devices showed a stable bipolar RS behavior with non-linear current-voltage characteristics for the high (HRS) and the low (LRS) resistance states. The obtained switching polarity and nearly area independent LRS values agree with a filamentary character of the RS behavior according to the valence change mechanism. The devices of 0.01 μm2 size with a 12 nm polycrystalline stoichiometric STO film were switched at a current compliance of 50 μA with voltages of about ±1.0 V between resistance states of about 40 kΩ (LRS) and 1 MΩ (HRS). After identification of the influences of the films' microstructures, i.e., grain boundaries and small cracks, the remaining RS properties could be ascribed to the effect of the [Sr]/([Sr] + [Ti]) composition of the ALD STO thin films. |