High frequency shear horizontal plate acoustic wave devices.

Area of Science:

• Materials Science
• Acoustics
• Electrical Engineering

Background:

• Shear horizontal acoustic waves in thin piezoelectric plates offer advantages for sensors and signal processing.
• Fabricating devices on these very thin plates is crucial for realizing their potential benefits.

Purpose of the Study:

• To develop and demonstrate a viable fabrication method for creating devices on ultra-thin piezoelectric plates.
• To realize shear horizontal plate acoustic wave (SH-PAW) devices on thin lithium niobate substrates.

Main Methods:

• A novel fabrication technique involving lapping a normally thick plate from the back side after device fabrication.
• Utilized this method to reduce substrate thickness to below 70 micrometers.

Main Results:

• Successfully fabricated devices on plates with thicknesses less than 70 micrometers.
• Achieved a shear horizontal plate acoustic wave (SH-PAW) delay line on a 60 micrometer thick Y-cut, X-propagation lithium niobate substrate.
• Demonstrated a fundamental resonant frequency above 25 MHz with an insertion loss below 7 dB, and a strong response near the third harmonic (75 MHz).

Conclusions:

• The developed fabrication method is effective for producing devices on ultra-thin piezoelectric plates.
• The realized SH-PAW delay line exhibits excellent performance characteristics, suitable for advanced sensor and signal processing applications.