AlN-based acoustic filters serve as crucial components in Radio Frequency (RF) communications. The current performances of these devices are limited on silicon substrates because of poor AlN crystal quality. This could be improved using ALD-grown 2D-MoS2 thin film as a template on silicon. Nevertheless, after deposition of thicker sputtered AlN films (≥ 200 nm), a systematic delamination of the AlN/MoS2 stack occurs which prohibits the integration of these materials in RF devices [1]. That is why a new elaboration process to grow thick AlN films with an improved crystal quality while avoiding the delamination issue is proposed in this work. This process is based on the chemical conversion of the MoS2 through a very thin 5 nm AlN seed layer using an ammonia (NH3) heat treatment [2]. A thorough XPS study was carried out to optimize a trade-off between the AlN thickness and the reactive annealing conditions allowing the diffusion of NH3 towards the underlaying MoS2 and its conversion into Mo(Ox)Ny. The synthesis and the analysis of molybdenum oxynitride by nitriding a well-controlled uniform molybdenum disulfide (MoS2) layer via a 700 °C ammonia NH3 reactive heat treatment without AlN seed layer was previously performed as reference [3,4]. The MoS2 nitriding reaction has also been demonstrated by in-plane XRD analysis and its progressive conversion has been monitored by in situ reflectance measurements. To support the XPS measurements mentioned above, the films were also characterized by combining Raman micro-spectroscopy and TEM (transmission electron microscopy). Moreover, ToF-SIMS analysis highlighted the MoS2 conversion even after a regrowth of a thick AlN film avoiding any interface (of interest AlN/MoNx) air exposure. Finally, this new synthesis route allowed to improve the crystal quality of thick AlN layers deposited on low cost silicon substrate.