Growth of ${\rm MgB}_{2}$ Thin Films In Situ by RF Magnetron Sputtering With a Pocket Heater
| Autor: | Mark Rzchowski, B. H. Moeckly, Seung Hyup Baek, Sanghan Lee, Xiaoxing Xi, Wenqing Dai, Qi Li, Ke Chen, C. B. Eom |
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| Rok vydání: | 2009 |
| Předmět: |
Materials science
Analytical chemistry chemistry.chemical_element Chemical vapor deposition Sputter deposition Condensed Matter Physics Electron beam physical vapor deposition Electronic Optical and Magnetic Materials Carbon film Vacuum deposition chemistry Sputtering Electrical and Electronic Engineering Thin film Boron |
| Zdroj: | IEEE Transactions on Applied Superconductivity. 19:2811-2814 |
| ISSN: | 1558-2515 1051-8223 |
| DOI: | 10.1109/tasc.2009.2018812 |
| Popis: | We have grown MgB2 thin films using RF magnetron sputtering combined with a pocket heater. This technique relies on a low-pressure environment for sputter deposition of boron and a high-pressure environment for thermal evaporation of Mg. We have obtained superconducting MgB2 thin films using substrate temperatures of 480-540degC and Mg furnace temperatures of 730-750degC. The Tc onset of the thin films increased from 21.6 K to 35 K with increasing substrate temperature due to better crystallization. Higher boron deposition rates also increase Tc. The highest Jc of the films at 5 K and near zero magnetic field is 1.5 MA/cm2 which is comparatively lower than the films grown using a pocket heater with boron deposition by chemical vapor deposition or electron beam evaporation. The chemical composition analysis by WDS exhibits a high concentration of oxygen and carbon in the MgB2 films, which is due to a high background base pressure and an impure B sputtering target. These results suggest that the Tc, Jc, and resistivity of MgB2 films are mainly determined by an inhomogeneous microstructure and superconducting percolation paths through impurity phases such as MgO. By comparison with carbon or oxygen doped films, the high impurity content in the sputtered MgB2 films might act as method to achieve high Hc2. |
| Databáze: | OpenAIRE |
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