Iowa State University Research Foundation, Inc.

Allen R Landin

Howard R Shanks

Stanley G Burns

Carl Gruber

David H Schmidt

Alan Paul Constant

Richard A Van Deusen

Bradley A Paulson

Dennis M Drees

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 method and system for detecting material bound on a surface of a piezoelectric resonator introduces a signal of a constant frequency through the sensing resonator and detects a change in the insertion phase shift of the resonator as a result of the binding of the material being detected on the surface of the resonator. Environmental effects on the measurement are effectively canceled by the use of a reference resonator driven by the same input signal. A multiple-port sensing device is provided which includes thin-film sensing and reference resonators monolithically formed on a substrate.

Method and system for detecting material using piezoelectric resonators

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

Amorphous silicon on insulator VLSI circuit structures

A method of making patterned metal oxide films on microelectronic wafer substrates. They are prepared by making a sol-gel of a metal oxide in combination with an ultraviolet light sensitive photo-active compound. The sol-gel is applied to a silicon wafer substrate, and the wafer subjected to a predetermined pattern of ultraviolet light to cause the photo-active compound to respond to the ultraviolet light. The wafer is thereafter aqueous alkali metal hydroxide washed to wash away the portions of the metal alkoxide film which have been exposed to UV light.

Method of making patterned metal oxide films comprising a sol-gel of

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Boone, IA, United States of America

Allen R Landin