Surface acoustic wave functional device

摘要

The surface acoustic wave functional element comprises a semiconductor layer provided on a piezoelectric substrate or a piezoelectric film substrate and makes use of interaction between a surface acoustic wave propagating on the substrate and electrons in the substrate layer, but has the semiconductor layer disposed outside above the propagation path for propagating a surface acoustic wave, comprises a plurality of grating electrodes perpendicularly above and to the propagation path and moreover the semiconductor layer comprises an active layer and a buffer layer lattice-matching thereto. By use of this surface acoustic wave functional element, a surface acoustic wave amplifier capable of providing a high amplification gain at a practical low voltage, a surface acoustic wave convolver having a higher efficiency than ever or the like are offered.