Structural and Morphological Features of HfN Magnetron Nanofilms with Varying Thickness

Purpose. Nanostructuring in hafnium nitride magnetron nanofilms with varying thickness.

Methods. Magnetron HfN nanofilms were deposited on silicon substrates in the direct current mode in an MVU TMMagna T facility (NIITM, Zelenograd). Obtaining nanofilms with a given thickness was achieved by varying the sputtering time in the range from 60 to 900 s. Nanoscale characterization of HfN nanofilms was carried out by atomic force microscopy and X-ray phase analysis. The fractal dimension was determined by the cube counting method.

Results. It was established that the growth of the HfN nanofilm proceeded according to the Volmer-Weber mechanism, the granulometric size distribution of nanoclusters in the HfN nanofilms was close to normal. Based on atomic force microscopic images of the nanofilm surface, both their average and root-mean-square roughnesses were calculated. According to the data of X-ray phase analysis in accordance with the Debye-Scherrer-Selikhov and Wolfe-Bragg formulas, the dimensions of the coherence region and the relative deformations of the crystal lattice are calculated, respectively.

Conclusion. Depending on the sputtering time, the coherent scattering regions L(t) changed nonlinearly, which indicated a structural transition with a characteristic change in the nanofilm surface morphology. The calculated values of the dependence of deformation changes – a(t) had an alternating form, that is, the process of formation of HfN nanofilms at the initial stage was accompanied by compression and then by tension. The time dependence of the fractal dimension D_f(t) always exceeded 2, which indicated that the nanofilms are three-dimensional. In this case, the dependence Df(t) reached Dfmax at ≈480 s. The alternating form of changes in dL/dt and da/dt and the existence of Dfmax at the corresponding sputtering times indicated the dominant growth of HfN nanofilms according to the Volmer-Weber mechanism with the formation of columnar structures.

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