Spintronics presents a modern research field driven by the urge for better-performing computing with low energy consumption. The general concept consists of adding the spin degree of freedom to conventional electronics giving access to a plethora of remarkable applications. An elegant strategy to design and create efficient spintronic systems relies on the use of topological insulators (TI) as spin sources. The induced metallic surface in such materials exhibits a robust spin polarisation protected by electronic band topology enabling an efficient charge-to-spin conversion. The transfer of spin’s angular momentum from the TI’s surface enables magnetization switching in a magnetic layer with perpendicular anisotropy (PMA). Such phenomenon is referred to as current-induced spin-orbit torques (SOT) allowing a deterministic manipulation of magnetization in a magnetic memory device. In particular, Bismuth antimony (BiSb) alloys outstand other TIs by their large spin-hall angle (θSH ≈ 52) generating a high spin-orbit field and a very low critical switching current density. The hastening quest for efficient SOT generators for future devices has led to multiple attempts to grow BiSb thin films on different substrates using various techniques. Crystallinity and defect density are crucial elements in preserving the topological properties and enabling on-top device fabrication. In our present work, we report the successful growth of Bi(x)Sb(1-x) films on (001)- and (111)-oriented GaAs substrates by Molecular beam epitaxy. Indeed, we provide an in-depth structural study and the growth key parameters' effect on the magneto-transport properties. As a result, films with excellent crystallinity and smooth surfaces could be obtained in the TI composition range with metallic surface features. Moreover, TI-based SOT heterostructures have been successfully grown on our films with the Co magnetic layer as a first step in the production of SOT-based magnetoresistive random access memories.