Structural and morphological features of magnetron films of bismuth telluride of n-type conductivity RF MR

Purpose of research. Characterization of n-type bismuth telluride nanofilms from the Bi2Te2,7Se0,3 target formed by high-frequency magnetron sputtering in Ar on a silicon substrate. Methods. High-frequency magnetron sputtering on a silicon substrate was carried out depending on changes in the control parameters (power P = 50 – 80 W and time t = 1800 – 2700 s) of sputtering. Characterization of magnetron nanofilms was carried out by X-ray phase analysis, atomic force microscopy, scanning electron microscopy, energydispersive X-ray microanalysis, digital holographic microscopy and Raman scattering. Statistical processing of AFM images of MNFs with the construction of autocorrelation functions using the direct Fourier transform, analysis of changes in the fractal dimensions of MNFs Results. Thicknesses were measured with precision using AFM, DHM, SEM and a specially developed EDS technique, and the growth rates of MNFs were calculated, their linear increase depending on P, and t was proven. According to the Raman and XRD data, it was found that polycrystalline MNFs are formed in the process of RF MR of Bi2Te2,7Se0,3, the crystallinity of which was achieved after annealing at 623 K. The sizes of the coherence regions, texturing, microstrains and interplanar deformation distortions of MNFs were calculated using the XRD patterns. Statistical processing of AFM images of MNFs was carried out with the determination of the fractal dimension and the construction of the ACF using the DFT. It is proved that MNFs have 3D dimensions and are formed by the mixed Stranski – Krastanov mechanism. Conclusion. In magnetron sputtered Bi2Te3 nanofilms with n-type conductivity, deformations of both signs were found: both compressive (∆а < 0) and tensile (∆a > 0). The calculated coherence sizes are consistent with the low level of crystallinity and weakly depend on the growth of both P and t. According to measurements by the “step” method of MNF thickness, the rate of their formation was V ≈ 0,6 nm/s.