This work reports on the deposition and characterization of different Al-content AlxGa1-xN thin films and subsequent GaN/AlxGa1 xN heterostructures using reactive magnetron sputtering deposition. Since achieving high-quality sputtered GaN still relies on the use of expensive substrates, high temperatures and intricate buffer layers, the use of AlGaN buffer has shown to enhance the quality of these films in a continuous process. Therefore, the main objective is to study the effect of the composition on the quality of the AlxGa1-xN films to determine the most suitable composition for the production of heterostructures using AlGaN as a buffer layer for GaN, in terms of c-axis orientation and crystalline structure, to make this material suitable for application in SAW devices. The AlxGa1-xN films were produced using different applied powers to the Al and Ga targets to vary the composition, with the Al content ranging from 0 ? x ? 0.47. Additionally, different substrates were used for the films, including glass and different Si orientations. The other deposition parameters were fixed for all processes, such as pressure (5 mTorr), temperature (550 °C), argon and nitrogen flow (7 and 14 sccm, respectively), and substrate position (90 mm above the Ga target). From the AlxGa1-xN films, a set of different compositions and AlxGa1-xN layer numbers were selected to produce the heterostructures on glass and Si(100) substrates. This approach allowed for the creation of highly c-oriented GaN films with minimized strains, defects, and surface roughness. The samples were characterized using energy dispersive spectroscopy, optical profilometry, X-ray diffraction, UV-Vis spectrophotometry, Raman spectroscopy, and scanning electron microscopy. The results showed a strong correlation between the properties of the AlxGa1-xN films and the composition, as well as an influence of the thickness of the samples. All samples displayed a wurtzite structure with a c-axis preferred orientation, which is desirable as a buffer layer, and this orientation increased with higher Al content. The quality of the films, in general, was evaluated using a combination of results from the different techniques, demonstrating that the Al content plays different roles in terms of strains, crystalline quality, bandgap, refractive index, and Raman phonon modes. For the heterostructures, the presence of an Al-rich buffer layer led to a more strongly c oriented GaN film, with no clear relation to the number or thickness of the buffer layer. Therefore, a high-Al content thin buffer layer successfully increased the quality of the GaN film. However, the use of multiple buffer layers with a compositional gradient further improved the surface of the GaN films without a clear improvement in the structural properties, but it also significantly increased the deposition time and the complexity of the process.