| AVS 54th International Symposium | |
| Electronic Materials and Processing | Wednesday Sessions |
| Session EM-WeA |
| Session: | Growth and Characterization of Complex Oxides |
| Presenter: | K. Fukaya, Nagoya University, Japan |
| Authors: | K. Fukaya, Nagoya University, Japan K. Sasaki, Nagoya University, Japan J. Gao, Nagoya University, Japan T. Kimura, Nagoya University, Japan M. Watanabe, Nagoya University, Japan M. Inoue, Nagoya University, Japan A. Fujimaki, Nagoya University, Japan H. Sugai, Chubu University, Japan |
| Correspondent: | Click to Email |
YBa2Cu3O7-d (YBaCuO) thin films are promising materials for high-temperature superconducting integrated-circuit devices. Magnetron sputtering deposition is a useful method for preparing YBaCuO thin films because of the cheaper process cost than pulsed laser deposition and metal organic chemical vapor deposition. This work reports gas-phase diagnostics of magnetron sputtering deposition of YBaCuO thin films. Because of the lack in detailed plasma diagnostics, the precursors for the deposition of YBaCuO films have not been identified yet. In this work, we measured two-dimensional distributions of the densities of Y, Ba, Cu, YO, BaO, and CuO by laser-induced fluorescence imaging spectroscopy. In addition, we adopted two-photon absorption laser-induced fluorescence for measuring one-dimensional distribution of the O atom density. By comparing the results of the gas-phase diagnostics with the properties of YBaCuO films, we identified the deposition precursors for obtaining fine YBaCuO films. A YBaCuO powder target, Ar/O2 mixture gas and a conventional rf magnetron sputtering source at 13.56 MHz were used in this experiment. The densities of Y, Ba, and Cu atoms were measured with varying the O2 flow ratio from 0 to 100% at a total gas pressure of 400 mTorr. The Cu density decreased gradually with the O2 flow ratio from 0 to 100%, which may be due to the decrease in the plasma density with the O2 flow ratio, resulting in the decrease in the sputtered Cu flux. In contrast, the Ba and Y densities decreased drastically with the O2 flow ratio, which is due to oxidation reaction in the gas phase. We observed the increases in the YO and BaO densities with the O2 flow ratio from 0 to 10%, indicating the production of YO and BaO from Y and Ba in the gas phase, while the CuO density was below the detection limit at all the discharge conditions. On the other hand, the O atom density increased with the O2 flow ratio from 0 to 20% and was saturated at O2 flow ratios higher than 20%. The O atom density was estimated to be much higher than the Cu density. According to the analysis of YBaCuO films deposited on MgO substrates (670 °C) placed at a distance of 3 cm from the target, fine YBaCuO films with high crystallinity were obtained at O2 flow ratios from 50 to 70%. Therefore, it is known by the present work that the deposition precursors for obtaining fine YBaCuO films are Cu, YO, BaO, and O.