## 3 Results and Discussion
### Structure Characterization of STO Films  
Figure 3 shows the diffraction patterns of STO films on silicon carbide deposited at different substrate temperatures and working gas pressures. The positions of reflections for bulk strontium titanate (PDF 35-734) are marked with vertical dotted lines, and the reflections of the substrate are marked with diamonds. The diffraction patterns for all the studied samples confirm the formation of pure strontium titanate with a perovskite structure. The films formed at a low substrate temperature are polycrystalline and strained--the diffraction patterns contain reflections (110) and (200), the position of which differs from the positions of reflections of an unstrained STO crystal. With an increase in the deposition temperature, the intensity of the reflection (200) increases and the angular positions of the peaks shift toward larger angles, which means a decrease in the unit cell parameter from 3.95 to 3.907 A. These trends are typical for all the considered working gas pressures, and indicate a significant improvement in the crystal structure of STO films and a decrease in internal stresses in the lattice.  
Figure 2: The height of the islands and the degree of coating of the substrate with islands for STO films grown at T\({}_{\mathrm{s}}\) = 800 \({}^{\circ}\)C.  
Let us compare the diffraction patterns of STO films deposited at \(\rm T_{s}\) = 900 \({}^{\circ}\)C, but at different pressures. The films exhibit a single-phase predominantly oriented structure (h00) at the absence of internal stresses in the lattice. The high temperature of the substrate ensures the active surface diffusion of particles before their incorporation into the STO lattice, which leads to the formation of an unstressed defect-free film. In addition, the  
Figure 3: Diffractograms of films obtained at different substrate temperatures and different working gas pressures.  
intensity of the (200) reflex of the film deposited at a pressure of 10 Pa is half an order of magnitude higher than the intensity of similar peaks of films formed at low pressures. Thus, the tendency to improve the structure is most pronounced for films deposited at elevated working gas pressure, which confirms the thesis of oriented crystallization at low supersaturation. Figure 4 shows comparative diffractograms of films of various thicknesses deposited under optimal conditions from the structure point of view (T\({}_{\rm s}\) = 900 \({}^{\circ}\)C, P = 10 Pa). With an increase in the thickness of the STO film, a significant improvement in its crystal structure is observed--the intensity of the (200) reflex increases significantly, and the peak width (FWHM \(\cong\) 0.6\({}^{\circ}\)) decreases to values close to those for a single crystal (FWHM \(\cong\) 0.3\({}^{\circ}\)). Trends in improving the structural quality of strontium titanate films with an increase in their thickness are noted in [55; 56].  
Figure 5 shows a typical image of the surface of an STO film on silicon carbide obtained using atomic force microscopy. The surface is a homogeneous granular structure without visual defects with grain sizes of about 100-150 nm and a surface roughness of 10-20 nm. The films under study have similar surface morphology, which is determined by the island growth mechanism in the considered technological regimes.  
Figure 4: Diffractograms of films of different thicknesses obtained at a pressure of 10 Pa and a substrate temperature of 900 \({}^{\circ}\)C.