Orthorhombic Ta3-xN5-yOy thin films grown by unbalanced magnetron sputtering: The role of oxygen on structure, composition, and optical properties

SURFACE & COATINGS TECHNOLOGY

卷:406

Article

Chang, Jui-Che¹  Eriksson, Fredrik¹  Sortica, Mauricio A.²  Greczynski, Grzegorz¹  Bakhit, Babak¹  Hu, Zhangjun³  Primetzhofer, Daniel^2,4  Hultman, Lars¹  Birch, Jens¹  Hsiao, Ching-Lien¹ 

[1] Linkoping Univ, Dept Phys Chem & Biol IFM, Div Thin Film Phys, SE-58183 Linkoping, Sweden

[2] Uppsala Univ, Tandem Lab, SE-75120 Uppsala, Sweden

[3] Linkoping Univ, Dept Phys Chem & Biol IFM, Div Mol Surface Phys & Nanosci, SE-58183 Linkoping, Sweden

[4] Uppsala Univ, Dept Phys & Astron, Div Appl Nucl Phys, SE-75120 Uppsala, Sweden

关键词: Ta3N5;    Magnetron sputtering;    XRD;    XPS;    ERDA;    Optical absorption spectroscopy;   

DOI  :  10.1016/j.surfcoat.2020.126665

来源: Elsevier

【 摘 要 】

Direct growth of orthorhombic Ta3N5-type Ta-O-N compound thin films, specifically Ta3-xN5-yOy, on Si and sapphire substrates with various atomic fractions is realized by unbalanced magnetron sputtering. Low-degree fiber-textural Ta3-xN5-yOy films were grown through reactive sputtering of Ta in a gas mixture of N-2, Ar, and O-2 with keeping a partial pressure ratio of 3:2:0.1 in a total working pressure range of 5-30 mTorr. With increasing total pressure from 5 to 30 mTorr, the atomic fraction of O in the as-grown Ta3-xN5-yOy films was found to increase from 0.02 to 0.15 while that of N and Ta decrease from 0.66 to 0.54 and 0.33 to 0.31, respectively, leading to a decrease in b lattice constant up to around 1.3%. Metallic TaNx phases were formed without oxygen. For a working pressure of 40 mTorr, an amorphous, O-rich Ta-N-O compound film with a high O fraction of similar to 0.48, was formed, mixed with non-stoichiometric TaON and Ta2O5. By analyzing the plasma discharge, the increasing O incorporation is associated with oxide formation on top of the Ta target due to a higher reactivity of Ta with O than with N. The increase of O incorporation in the films also leads to a optical bandgap widening from similar to 2.22 to similar to 2.96 eV, which is in agreement with the compositional and structural changes from a crystalline Ta3-xN5-yOy to an amorphous O-rich Ta-O-N compound.

【 授权许可】

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