Reactive magnetron sputtering of tungsten target in krypton/trimethylboron atmosphere

THIN SOLID FILMS

卷:688

Article

Magnuson, Martin¹  Tengdelius, Lina¹  Eriksson, Fredrik¹  Samuelsson, Mattias¹  Broitman, Esteban^1,2  Greczynski, Grzegorz¹  Hultman, Lars¹  Hogberg, Hans¹ 

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

[2] SKF Res & Dev Ctr, NL-3439 MT Nieuwegein, Netherlands

关键词: W-B-C films;    Reactive magnetron sputtering;    Trimethylboron;    Nanoindentation;    X-ray photoelectron spectroscopy;    Thin film X-ray diffraction;    Scanning Electron microscope;   

DOI  :  10.1016/j.tsf.2019.06.034

来源: Elsevier

【 摘 要 】

W-B-C films were deposited on Si(100) substrates held at elevated temperature by reactive sputtering from a W target in Kr/trimethylboron (TMB) plasmas. Quantitative analysis by X-ray photoelectron spectroscopy (XPS) shows that the films are W-rich between similar to 73 and similar to 93 at.% W. The highest metal content is detected in the film deposited with 1 sccm TMB. The C and B concentrations increase with increasing TMB flow to a maximum of similar to 18 and similar to 7 at.%, respectively, while the O content remains nearly constant at 2-3 at.%. Chemical bonding structure analysis performed after samples sputter-cleaning reveals C-W and B-W bonding and no detectable W-O bonds. During film growth with 5 sccm TMB and 500 degrees C or with 10 sccm TMB and 300-600 degrees C thin film X-ray diffraction shows the formation of cubic 100-oriented WC1-x with a possible solid solution of B. Lower flows and lower growth temperatures favor growth of W and W2C, respectively. Depositions at 700 and 800 degrees C result in the formation of WSi2 due to a reaction with the substrate. At 900 degrees C, XPS analysis shows similar to 96 at.% Si in the film due to Si interdiffusion. Scanning electron microscopy images reveal a fine-grained microstructure for the deposited WC1-x films. Nanoindentation gives hardness values in the range from similar to 23 to similar to 31 GPa and reduced elastic moduli between similar to 220 and 280 GPa in the films deposited at temperatures lower than 600 degrees C. At higher growth temperatures, the hardness decreases by a factor of 3 to 4 following the formation of WSi2 at 700-800 degrees C and Si-rich surface at 900 degrees C.

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