US Government As Represented by the Secretary of the Army

Richard H Wittstruck

Arthur D Ballato

Yicheng Lu

Xiaojun Tong

Mitra Dutta

Paul H Shen

Jagadeesh Pamulapati

Peter E Norris

Thomas R Aucoin

Peter A Zawadzki

Jing Zhao

William R Baarck

Thin film bulk acoustic wave sensors with coatings of biological and chemical materials, multiple electrode depositions and a piezo-active thin film transducer layer are hosted on a substrate. The thin film bulk acoustic wave sensor suite, or T-BASS, produces a low-voltage, IC-compliant thickness-directed electric field that is substantially uniform over a substantial portion of the active area of the BAW structure. The BAWs produced are essentially extensional plane waves propagating away from the substrate surface and having phase progression substantially oblique to the substrate surface. For BAW applications requiring sensing by an active layer, it would be most desirable to have an electrode structure that is both IC-compliant and can be energized from a low-voltage source of electrical energy. The thin film BAW sensors are compatible with IC fabrication and processing techniques, such as photolithography. Both single channel and multiple channel thin film bulk acoustic wave sensors are provided.

Thin film bulk acoustic wave sensor suite

An Interdigital Bulk Acoustic-Wave Transducer (IBAT) device is provided with pairs of exciting electrode fingers disposed sufficiently close together on the piezoelectric substrate and dielectric coating over the exciting electrode fingers to generate an IC-compatible voltage at relatively high electric field strength, resulting in a reduced region of excitation and uniform electric field strength distribution. The IBAT advantageously produces a lateral electric field substantially uniform over a substantial portion of the active BAW structure area, reducing, or virtually eliminating sharp voltage spikes, an electrical field produced by the low voltages resident on integrated circuit (IC) chips, usually of a magnitude of 10 volts, or lower, the planar electrode structure being compatible with IC processing techniques, such as photolithography and the BAWs produced thereby being essentially plane waves, with propagation away from, but with phase progression substantially parallel to, the substrate surface. Numerous IBAT structural arrangements are possible by advantageously over-coating the IBAT electrode finger stripes with an insulating dielectric in different configurations, and any possible configuration achieved through over-coating is considered to be within the contemplation of the devices and methods of the present invention. Interdigital bulk acoustic wave transducers and methods for exciting bulk acoustic waves with interdigital electrode fingers are also provided.

Lateral field excitation of bulk acoustic waves from an IC-compliant low voltage source

An MQW is fabricated such that at a particular level of purely mechanical ress/strain the optical properties of the MQW are altered by breaking the heavy and light hole degeneracy (splitting of the heavy and light holes in the valence band) of the MQW in the E-k domain. In a preferred embodiment of the invention ring electrical contacts are disposed on the MQW and the entire MQW structure, including electrical contacts is mounted on a piezoelectric substrate, with the proper crystallographic orientation and strain induced orientation, via an epoxy. In operation, a bias is applied to the MQW structure and the piezoelectric substrate. The bias causes quantum decoupling of the heavy and light holes; however, the bias also will cause the piezoelectric material to move, which will induce a strain on the MQW structure. This strain will, in turn, also induce a decoupling of the heavy and light holes, but to a greater degree than the decoupling induced by the electrical bias and therefore, the absorption of the MQW will altered, thereby polarizing optical signal incident to (or through) the device.

Dynamic modulation of quantum devices

Micro-scale and nano-scale devices which achieve high frequency signals ug materials having increased electron saturation velocity. These devices have frequencies in the terahertz range with high temperature and radiation hard characteristics. The transit time device includes a substrate, a buffer layer and an epitaxial layer made of a material in the 43 m and 6 mm crystallographic point groups and associated alloys, and at least two contacts on the device. In operation, one contact is forward biased and the other is reversed biased. Applications for this devices include transit-time-based oscillators for use in military and civilian radar receivers, logic devices, burglar alarm and proximity alarm systems.

Method for high frequency device operation with high temperature and

The present invention provides for a chemical vapor deposition reactor cher which is fitted with a rotatable and vertically movable susceptor/wafer carrier. The susceptor/wafer carrier, which is a large diameter disk, provides the reactor with the capability of varying the plasma-substrate distance. As those skilled in the art will appreciate, such a susceptor allows high deposition rates to be achieved for a given power level because the flux of the reactant can be increased due to the high speed rotation which will decrease boundary layer thickness during growth. The ability to adjust the source-substrate distance gives more flexibility than fixed dimensional systems. Further, it allows damage in the thin films to be minimized by simple adjustments to the susceptor/wafer carrier. Because the damage to the thin films is minimized, it makes pulsed operation practical and therefore, the films may be grown in an atomic layer epitaxy mode to produce films of high quality and uniformity.

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Howell, NJ, United States of America

Richard H Wittstruck