▎ 摘　　要

NOVELTY - The method involves forming a high velocity layer (16) on a substrate (12). A medium velocity layer (18) is formed on the high velocity layer. A low velocity layer (20) is formed on the medium velocity layer. A piezoelectric layer (22) is formed on the low velocity layer and an electrode is formed on the piezoelectric layer. A buffer layer (14) is formed on the substrate before forming the high velocity layer. The buffer layer comprises silicon oxide. The high velocity layer comprises graphene. The high velocity layer comprises boron carbide. The medium velocity layer comprises silicon oxynitride (SiON). The medium velocity layer comprises silicon oxycarbonitride (SiOCN). The low velocity layer comprises titanium oxide (TiO2). The low velocity layer comprises silicon oxycarbide (SiOC). USE - Method for fabricating surface acoustic wave (SAW) device (claimed) for hybrid bonding package in mobile communication industry. ADVANTAGE - The method enables fabricating the surface acoustic wave (SAW) device in an effective manner. The SAW device is miniaturized for reaching high performance, and has high performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a surface acoustic wave SAW device. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the method for fabricating surface acoustic wave (SAW) device. 12Substrate 14Buffer layer 16High velocity layer 18Medium velocity layer 20Low velocity layer 22Piezoelectric layer