PURPOSE: To obtain a surface acoustic wave amplifier, in which a large amplification degree is generated at low voltage by forming a semiconductor active layer having high carrier mobility onto a piezoelectric substrate.
CONSTITUTION: A laminated structure 6 consists of a piezoelectric substrate 1, a semiconductor buffer layer 2 on the substrate 1 and a semiconductor active layer 3 having a film thickness in a range of 5 nm or larger to 500 nm or smaller. The lattice constant of the semiconductor buffer layer 2 is equalized to the lattice constant of the semiconductor active layer 3 or has a value close to the lattice constant of the semiconductor active layer 3 at that time. Reed screen-shaped input/output electrodes 4, 5 are formed onto the piezoelectric substrate 1 in the amplifier, the laminated structure 6 is arranged between both electrodes 4, 5, and electrodes 7 are formed to the semiconductor active layer 3.
SHIBATA YOSHIHIKO
SUGANO YASUTO
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