| 摘要 |
PURPOSE:To improve capacities of a delay time temperature coefficient and an electromechanical coupling coefficient and to improve the reliability of a surface acoustic wave element by forming an electrode, which converts an electrical signal to a surface acoustic wave, and a silicon dioxide film having a prescribed thickness on a lithium borate single crystal plate. CONSTITUTION:An electrode 2 which converts the electrical signal to a surface acoustic wave is formed on a lithium borate substrate 1, and a silicon dioxide film 3 having a prescribed thickness is formed on the substrate 1 including the electrode 2. The thickness of the silicon dioxide film 3 is set within a range of 0.9-2.3 in terms of normalized film thickness Kh [K=2pi/lambda (lambda is the wavelength of the surface acoustic wave)]. Thus, capacities of a delay time temperature coefficient TCD and an electromechanical coupling coefficient K<2> are improved to improve the reliability of the surface acoustic wave element. |
