Saw filter manufactured by using GaN single crystal thin film, and manufacturing method therefore

A SAW filter of a high frequency band, comprising:

• a single crystal substrate selected from the group consisting of an α-Al2O3 substrate, a silicon substrate having (100) or (111) faces, a SiC substrate, and a MgAl2O4 substrate;
• a GaN piezoelectric single crystal thin film of [0001] direction formed to a thickness of 0.3-300 μm upon said substrate;
• an IDT electrode pattern formed upon said GaN piezoelectric single crystal thin film;
• and
• a GaN buffer layer formed between said single crystal substrate and said GaN single crystal thin film to a thickness of 200-500 Å.

A method for manufacturing a SAW filter of a high frequency band, comprising the steps of:

• preparing a single crystal substrate selected from the group consisting of an α-Al2O3 substrate, a silicon substrate having (100) or (111) faces, a SiC substrate, and a MgAl2O4 substrate;
• forming a GaN buffer layer to a thickness 200-500 Å upon said substrate;
• epitaxially growing a GaN piezoelectric single crystal thin film of [0001] direction to a thickness of 0.3-300 μm upon said buffer layer;
• and
• forming an IDT electrode pattern upon said GaN piezoelectric single crystal thin film.