Iowa State University Research Foundation, Inc.

Stanley G Burns

Howard R Shanks

Robert J Weber

Allen R Landin

Carl Gruber

David H Schmidt

Frank R Jeffrey

Alan Paul Constant

Steve D Braymen

Philip H Thompson

Allan P Constant

An integrated thin film transistor on insulator circuit made up of a number of thin film transistors formed with small feature size and densely packed so as to allow interconnection as a complex circuit. An insulating substrate, preferably flexible, serves as the support layer for the integrated circuit. Control gate metallization is carried on the insulating substrate, a dielectric layer is deposited over the control gate, and an amorphous silicon layer with doped source and drain regions deposited on the dielectric layer. Trenches are formed to remove the amorphous silicon material between transistors to allow highly dense circuit packing. An upper interconnect level which forms connections to the source and drain and gate regions of the thin film transistors, also interconnects the transistors to form more complex circuit structures. Due to the dense packing of the transistors allowed by the trench isolation, the interconnecting foils can be relatively short, increasing the speed of the circuit.

Method of making amorphous silicon on insulator VLSI circuit structures

A thin film floating gate transistor with improved dielectric structure. The dielectric structure serves the purpose of encapsulating the floating gate and also interfacing with the semiconductor material, .alpha.-Si:H. It thus must meet a variety of requirements. In order to provide long memory retention times, the dielectric material, at least in the regions encapsulating the floating gate, must have a high resistivity, on the order of 10.sup.17 ohm-cm or better. Silicon dioxide is the preferred material for encapsulating the floating gate. However, since silicon dioxide creates a high density of defect state when interfaced with the .alpha.-Si:H layer. An interface layer, substantially free of oxide, is interposed between the high resistivity layer and the .alpha.-Si:H. Preferably, the interface portion of the dielectric layer is silicon nitride. In some cases, it is desirable to replace the entire dielectric structure, or at least the interface layer with aluminum nitride.

Dielectric for amorphous silicon transistors

A non-planar electronic light-emitting display has a display area divided into a matrix of pixels. Each pixel includes two primary elements, an electronic driver and a light-emitting diode based on a light-emitting polymer. The electronic driver is a thin film transistor device of amorphous silicon formed on the insulating substrate. The diode has a first electrode connected to and driven by the electronic transistor, a layer of light-emitting polymer deposited on the electrode, and an overlying electrode normally biased on. Energization of the driver biases the diode to cause the polymer to emit light. Each pixel is configured with the two-component structure described above, and row and column lines to the matrix of pixels are decoded by the drivers to cause selective illumination of the pixels.

Flexible panel display having thin film transistors driving polymer

Amorphous silicon on insulator VLSI circuit structures

A non-crystalline silicon--preferably a-Si:H--active device for use in a large-scale hardware implementation of an artificial neural network system having an analog and digital mixed morphology. A plurality of a-Si:H thin-film transistors (TFTs) implement addition, multiplication and weighting functionality and are arranged in a highly-connected morphology with other active and passive semiconductor elements. Electrical signals are selectively applied to metal plates and light-emitting devices in order to locally or globally alter the threshold characteristics of the TFTs.

Non-crystalline silicon active device for large-scale digital and analog

A cointegrated high frequency oscillator including a thin film resonator and active devices formed on the same semiconductor substrate and by a process which is compatible with formation of both the thin film resonator and the active devices. The processes utilized in formation of the thin film resonator are adapted to microelectronic processing techniques such that the steps of formation of the active devices and the thin film resonator can be intermixed to the degree necessary to allow, for example, the metallization layers to serve as elements both of the active devices and the thin film resonator.

High frequency oscillator comprising cointegrated thin film resonator

An electronically controlled oscillator capable of operating in the rf/microwave frequency range, and using a stacked crystal filter as the frequency determining element in the oscillator. A non-linear element including an appropriately biased high frequency amplifier has the stacked crystal filter connected in its feedback path and provides a loop gain of greater than 1 to meet one aspect of the Barkhausen criteria. An electronically variable impedance, such as a hyperabrupt junction varactor, is connected in the feedback loop along with the stacked crystal filter to controllably insert a phase adjustment into the feedback path, to be compensated by a phase adjustment by the stacked crystal filter, thereby to controllably maintain a loop phase shift which is an integral number of 2.pi. radians at the oscillator frequency, and to vary the oscillator output frequency about the frequency of the stacked crystal filter in a controllable fashion. In a further implementation of the electronically controlled oscillator, an overmoded stacked crystal filter is utilized which has a comb response, and a second delay stacked crystal filter is also employed in the feedback path for providing an adjustable phase delay for causing the oscillator to controllably operate at the respective responses in the comb of responses of the overmoded stacked crystal filter.

Electronically-tuned thin-film resonator/filter controlled oscillator

Apparatus and method for measuring the moisture content of wood and paper products utilizing the dependency of the resistance or capacitance of such products upon moisture content. A resistance or capacitance-controlled oscillator circuit is completed by electrical connection to a product. Electrical connection of the resistance-controlled oscillator embodiment is accomplished by either application of a conducting contact grid pattern to a product or by forming a parallel plate probe incorporating the product therein. Electrical connection of the capacitance-controlled oscillator embodiment may also be accomplished by forming a parallel plate probe incorporating the product therein or by insertion of a plurality of conductive cylinders in parallel combination into flutes of a corrugated paperboard product when such a product is to be subject to measurement.

Growing community of inventors

Ames, IA, United States of America

Stanley G Burns