Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1999-07-14
2001-10-09
Budd, Mark O. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S322000, C310S324000, C310S31300R, C310S341000
Reexamination Certificate
active
06300706
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to III-V or II-VI (or more generally, compound) semiconductors that have crystal symmetry so as to be piezoelectric (usually 4-bar 3 m or 6 mm). In particular, this invention relates to the monolithic creation of frequency stable resonators and/or mechanical resonant or non-resonant sensors along with electronic circuitry ancillary to the device. The invention may use reduced temperatures to stabilize and improve the operations of the device.
BACKGROUND OF THE INVENTION
Stable frequency sources, such as clocks, are required for numerous electronic applications. For example, microprocessors need a clock in order to function. Currently, a discrete piezoelectric frequency control device, such as a quartz oscillator, provides a stable frequency signal to integrated circuit electronic components. This hybrid combination of a piezoelectric oscillator together with an integrated circuit, is much larger than the integrated circuit by itself. In order to reduce the total size of an electronic device, the piezoelectric frequency source should be fabricated in the semiconductor substrate, to provide a monolithic, integrated acoustic/electronic device that is much smaller than the hybrid combination.
New technology has emerged which does fabricate the piezoelectric source into a semiconductor to form a monolithic acoustic/electronic integrated circuit. However, when operating at room temperature, the conductivity of the semiconductor reduces the quality factor Q, which in turn degrades the performance of the acoustic device. As a result, such monolithic acoustic/electronic devices have not achieved the high performance, low phase noise, or high Q of the discrete quartz oscillators used in the hybrid circuits.
Therefore, a strong need to improve the performance of piezoelectric semiconductor frequency sources exists. This need is met be providing a constant, low temperature environment, along with electronic feedback circuitry to compensate for fluctuations in temperature.
Similarly, at high temperatures, there is a need for a piezoelectric resonator which is able to function at high temperatures.
SUMMARY OF THE INVENTION
The invention includes an article of manufacture comprising an integrated circuit and an acoustic device fabricated in the integrated circuit. In one embodiment, the article of manufacture includes a heat sink for providing a cryogenic temperature to the article. In another embodiment, the invention includes electronic circuitry for providing feedback to the acoustic device. The invention further includes a piezoelectric acoustic device that functions at high temperatures.
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Ballato Arthur
Grudkowski Thomas W.
Budd Mark O.
Tereschuk George B.
The United States of America as represented by the Secretary of
Zelenka Michael
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