Preparation method of AlN film

The invention provides a preparation method of an AlN film. The preparation method comprises the following steps of: providing a substrate; depositing a bottom AlN film layer on the substrate in a sputtering mode, so as to obtain an initial film; and carrying out heat treatment layer preparation treatment on the initial film for multiple times, and forming multiple AlN film layers on the initial film until the total thickness of the AlN film layers on the substrate reaches a target value, so as to obtain the AlN film. According to the preparation method of the AlN film of the technical schemes provided by the invention, the AlN film is formed through sputtering deposition, the AlN film is formed through repeated heat treatment layer preparation treatment, the AlN template with higher crystal quality and lower stress is obtained, the preparation process is simple, effective and stable, the cost is low, and industrial application is facilitated. 本发明提供一种AlN薄膜的制备方法，包括以下步骤：提供一衬底；在所述衬底上溅射沉积一层底层AlN薄膜层，得到一初始薄膜；多次对所述初