Phonon Corporation

Tom A Martin

Pierre A Dufilie

Joseph V Adler

A surface acoustic wave (SAW) device comprising a piezoelectric substrate having a working surface with an active zone capable of propagating an acoustic wave on said working surface; at least one interdigital transducer on the working surface, having interdigital fingers aligned in the active zone for inducing or receiving surface acoustic waves in the active zone; and a heating element on the working surface; wherein the transducer, heating element and preferably a temperature sensor are monolithically formed on the substrate.

Monolithically applied heating elements on saw substrate

A surface acoustic wave (SAW) device includes a piezoelectric crystal substrate on which an acoustic channel is formed, at least one electro-mechanical transducer operatively associated with the acoustic channel, and an encapsulating casing having a cover spaced above the acoustic channel and thereby defining a sealed volume around the substrate. A mass deposition device within the casing is spaced between the acoustic channel and the cover, preferably as gold-coated heating wire spanning the acoustic channel and having ends that are connectable to an electric power source outside the casing. Stress and aging shifts can be induced after sealing of the cover. Tuning is achieved by evaporating metal molecules off the heated wire onto the acoustic channel as the frequency is monitored, until the mass loading of metal molecules on the transducer produces the target frequency.

SAW device and method for post-seal frequency trimming

A surface acoustic wave (SAW) device comprising at least one heating element formed on the substrate; at least one temperature sensor having a first electric component on the substrate whose resistance varies with the temperature of the substrate and a second electric component whose resistance does not vary; and a temperature controller including an operational amplifier bonded in thermally conductive relationship to the substrate. The operational amplifier is responsive to the output of the temperature sensor to apply power to the heating element and thereby maintain the temperature of the substrate within a predetermined temperature range. The transducer, heating element, and first component are monolithically formed on the substrate, and only three electrical connections are on the substrate at voltage to off-SAW die points.

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Canton, CT, United States of America

Tom A Martin