General Electric Company

Jack D Kingsley

Robert F Kwasnick

George E Possin

Ching-Yeu Wei

Harold G Parks

Kei-Hsiung Yang

David Michael Hoffman

Richard J Saia

William W Piper

Stanley Joseph Lubowski

Jacob Charles Bortscheller

Henry H Woodbury

Chukka Srinivas

Roger S Ehle

Robert F Kwansnick

A solid state radiation imager that exhibits reduced capacitive coupling between pixel photodiodes and readout data lines, and thus further has reduced phantom images or image artifacts, includes a plurality of shield lines disposed at the same level of the device as the scan lines and associated gate electrodes for the switching transistors. The shield lines include respective pixel shielding spurs oriented along the same axis as the data lines and disposed between portions of the pixel photodiode and adjacent portions of the data lines. The shield lines are typically coupled to a shield voltage source such that the shield lines are maintained at a common potential.

Solid state radiation imager with gate electrode plane shield wires

A low noise fluoroscopic radiation imager includes a large area photosensor array having a plurality of photosensors arranged in a pattern so as to have a predetermined pitch, and a low noise addressable thin film transistor (TFT) array electrically coupled to the photosensors. The TFT array includes a plurality of low charge retention TFTs, each of which have a switched silicon region that has an area in microns not greater than the value of the pitch of the imager array expressed in microns. The portion of the switched silicon region underlying the source and drain electrodes of the TFT is not greater than about 150% of the portion of the switched silicon region in the channel area of the TFT. The ratio of the TFT channel width to channel length (the distance between the source and drain electrodes across the channel) is less than 20:1, and commonly less than 10:1, with the channel length in the range of between about 1 .mu.m and 4 .mu.m. The photosensor array also includes crossover regions between address lines that have substantially no silicon therebetween so that no switched silicon region exists at the crossovers.

Solid state fluoroscopic radiation imager with thin film transistor

A radiation imager includes a photosensor barrier layer disposed between an amorphous silicon photosensor array and the scintillator. The barrier layer includes two strata, the first stratum being silicon oxide disposed over the upper conductive layer of the photosensor array and the second stratum is silicon nitride that is disposed over the first stratum. The photosensor barrier layer has a shape that substantially conforms to the the shape of the underlying upper conductive layer and has a maximum thickness of about 3 microns. The silicon oxide and silicon nitride are deposited in a vapor deposition process at less than about 250.degree. C. using tetraethoxysilane (TEOS) as the silicon source gas.

Method of fabricating solid state radiation imager with high integrity

Solid state radiation imager with high integrity barrier layer and

A radiation imaging system includes an image detector assembly coupled to an image processor. The image detector assembly includes a photosensor pixel array which is disposed in a plurality of sequential imaging positions pursuant to a predetermined imaging cycle. The image processor stores the respective image data signals from each photosensor pixel in the array from each respective imaging position in a given imaging cycle in an unfiltered interleaved data set, and then apply the unfiltered data to a deblurring filter to generate a non-aliased high resolution data set appropriate for driving a display and analysis module.

High resolution radiation imaging system

A photosensitive element has a two tier passivation layer disposed between the top contact layer and the amorphous silicon photosensor island. The passivation layer includes an inorganic moisture barrier layer which is disposed at least over the sidewalls of the photosensor island. The inorganic material forming this layer is preferably silicon nitride or silicon oxide. An organic dielectric layer is disposed over the moisture barrier layer and the photosensor island except for a selected contact area on the top surface of the photosensor island where the top contact layer is in electrical contact with the amorphous silicon material of the photosensor island. The organic dielectric material is preferably a polyimide.

Photosensitive element with two layer passivation coating

A dual dielectric structure is employed in the fabrication of thin film field effect transistors in a matrix addressed liquid display to provide improved transistor device characteristics and also to provide both electrical and chemical isolation for material employed in the gate metallization layer. In particular, the use of a layer of silicon oxide over the gate metallization layer is not only consistent with providing the desired electrical and chemical isolation, but also with providing redundant gate metallization material to be employed beneath source or data lines for electrical circuit redundancy. Gate line redundancy is also possible. The electrical and chemical isolation provided by the dual dielectric layer reduces the possibilities of short circuits occurring in the display. The absence of short circuits together with the improved redundancy characteristics significantly increase manufacturing yield. As display sizes increase, the yield problem becomes more and more significant, generally growing as the square of the diagonal measurement of the screen. The structure in the present invention also significantly reduces gate leakage current. In the process and structure of the present invention, gate electrode material is separated from semiconductor material by the aforementioned dual dielectric, typically comprising layers of silicon oxide disposed beneath a layer of silicon nitride which is, in turn, disposed beneath the active amorphous silicon semiconductor material.

Dual dielectric field effect transistors for protected gate structures

A radiation imager includes a photodetector array having topographically patterned surface features, which include support islands disposed over the active portion of one or more photodetectors in the photodetector array. A structured scintillator array having individual columnar scintillator elements is disposed in fixed relation to the photodetector array so that the individual scintillator elements are disposed on scintillator support islands. A barrier layer is disposed between the support islands and the photodetector array to minimize chemical interactions between the material forming the support island and the underlying photodetector array during the fabrication process. After the support islands have been patterned, the scintillator elements are grown by selectively depositing scintillator material on the support islands.

High sensitivity, high resolution, solid state x-ray imaging device with

A radiation imager having a scintillator mated to a photodetector array has a moisture barrier disposed over at least the portion of the scintillator exposed to the incident radiation. The moisture barrier, which is substantially impervious to moisture, is both radiation transmissive and optically reflective. A pellicle layer may be disposed between the top surface of the scintillator array and the moisture barrier to provide a stable surface to which the moisture barrier can adhere. The moisture barrier normally comprises an optically reflective layer and a moisture sealant layer. The optically reflective layer is comprised of a reflective metal or dielectric layers have different refractive indices and the moisture sealant layer is comprised of a silicone potting compound. A hardened protective window may be situated over the top surface of the moisture barrier.

Solid state radiation imager having a reflective and protective coating

An electronic x-ray imaging array is provided by combining a two-dimensional photosensitive array with a structured scintillator array, having a common array pattern and suitable alignment marks thereon, by bonding them face-to-face in alignment for direct coupling of x-ray luminescence from the scintillator array to the photosensitive array.

Method of forming an x-ray imaging array and the array

A dual dielectric structure is employed in the fabrication of thin film field effect transistors in a matrix addressed liquid display to provide improved transistor device characteristics and also to provide both electricial and chemical isolation for material employed in the gate metallization layer. In particular, the use of a layer of silicon oxide over the gate metallization layer is not only consistent with providing the desired electrical and chemical isolation, but also with providing redundant gate metallization material to be employed beneath source or data lines for electrical circuit redundancy. Gate line redundancy is also possible. The electrical and chemical isolation provided by the dual dielectric layer reduces the possibilities of short circuits occurring in the display. The absence of short circuits together with the improved redundancy characteristics significantly increase manufacturing yield. As display sizes increase, the yield problem becomes more and more significant, generally growing as the square of the diagonal measurement of the screen. The structure in the present invention also significantly reduces gate leakage current. In the process and structure of the present invention, gate electrode material is separated from semiconductor material by the aforementioned dual dielectric, typically comprising layers of silicon oxide disposed beneath a layer of silicon nitride which is, in turn, disposed beneath the active amorphous silicon semiconductor material.

In a thin film field-effect transistor, source and drain electrodes each include at least one, respective, narrowed, elongated portion. These elongated source and drain portions are oriented in parallel and in adjacent relation to each other, and a respective, complete longitudinal section of each elongated portion overlays a gate electrode. The resulting FET may be fabricated with readily-achievable photolithographic alignment precision as between the source and drain electrode configuration and the gate electrode, and achieves acceptably low source-to-gate and drain-to-gate parasitic capacitances.

Thin film field-effect transistors with tolerance to electrode

A solid state detector in which each scintillator is optimally configured and coupled with its associated sensing diode in a way which exploits light piping effects to enhance efficiency. Preferably, the detector is modular in nature. Each scintillator is a crystal having an index of refraction which differs as a function of direction through the crystal lattice, with the lowest index of refraction being parallel to the cleavage plane. The sides of each scintillator bar conform with the cleavage plane and are highly polished to light pipe photons created in the scintillator to the rear face for collection by an associated photodiode. The rear face is roughened to de-trap light, allowing transfer from the scintillator to the diode. Optical coupling means join the scintillators to their associated diodes to further enhance light transfer.

Solid state detector

A layer of X-ray photoconductor is sandwiched between electrodes for conversion of X-radiation to an electrical signal. The photoconductor layer is biased, and films of zinc sulfide may be used between the layer and each electrode, to minimize dark current. Arrays of solid state radiation detectors utilizing the biased photoconductive conversion layer are also disclosed.

Solid state radiation detector and arrays thereof

A method and apparatus for ion-valve radiography, utilizing a high-pressure gaseous material for conversion of differentially-absorbed X-radiation into electrostatic charge images, utilizes a closed chamber and a charge-image-receiving mesh structure movable between an ion source and ion detection means, to provide direct charge readout without requiring opening of the imaging chamber.

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Schenectady, NY, United States of America

Jack D Kingsley