摘要:
An imager array includes a substrate with a plurality of superimposed layers of electrically conductive and active components. Sets of scan and data lines are electrically insulated from one another and also from a common electrode and active array components by dielectric material. Protection of the active components against static charge potential includes resistive means between the common electrode and a ground ring conductor around the array elements and in particular a thin film transistor circuit with a parallel pair of opposite polarity diode connected field effect transistors to safely drain the static charge during subsequent fabrication, test and standby period of the imager, while remaining in circuit during imager operation. Further electrostatic charge protection is provided to the array by an protective apparatus adapted to support the radiation imager while electrically contacting its ground ring to facilitate handling and processing while protecting against electrostatic charge damage during fabrication and testing, and enabling the positioning and bonding of the flexible external connections to the contact pads of the imager. Provision is made to enable heat and pressure for thermode bonding through the fixture to the contact pads while the imager is secured within the fixture.
摘要:
A light block material disposed over the photosensitive region of a switching device (e.g., TFT) of a radiation imager is disclosed. The light block material prevents optical photons emitted from a scintillator from passing into the switching device and being absorbed. Cross-talk and noise in the imager are thereby reduced. Also, non-linear pixel response and spurious signals passing to readout electronics are avoided. Optionally, opaque caps comprising the same light block material may be included in the imager structure. The caps cover contact vias filled with a common electrode and located in the contact finger region of the imager. The integrity of the filled vias is thereby maintained during subsequent processing. Also disclosed is a radiation imager containing these structures.
摘要:
A radiation imager includes a photosensor array that is coupled to a scintillator so as to detect optical photons generated when incident radiation is absorbed in the scintillator. The imager includes an optical crosstalk attenuator that is optically coupled to a first surface of the scintillator (that is, the surface opposite the photosensor). The optical crosstalk attenuator includes an optical absorption material that is disposed so as to inhibit reflection of optical photons incident on the scintillator first surface back into the scintillator along selected crosstalk reflection paths. The crosstalk reflection paths are those paths oriented such that optical photons passing along such paths would be incident upon photosensor array pixels that are outside of a selected focal area corresponding to the absorption point in the scintillator. The imager further may include an optical screen layer that is optically coupled to the scintillator second surface so as to be disposed between the scintillator and the photosensor array. The optical screen layer is made of a substantially transparent material selected to have a critical index of refraction so as to cause preferential reflection of optical photons that are incident on the screen layer to reduce optical crosstalk.
摘要:
A radiation imager having a plurality of photosensitive elements has a two-tier passivation layer disposed between the top patterned common electrode contact layer and respective photosensor islands. The top passivation layer is a polymer bridge member disposed between adjacent photodiodes so as to isolate defects such as moisture-induced leakage in any bridge island layer to the two adjacent photodiodes spanned by the bridge island.
摘要:
RD-25953-17-A method of fabricating an imager array having a plurality of pixels is provided in which each pixel is made up of a photodiode and a corresponding thin film transistor (TFT) switching device, the method including the steps of depositing materials to form the photodiode island and to form a TFT body over a gate electrode, then depositing a layer of source/drain metal over the silicon layers of the TFT body, and over a common dielectric layer, removing sections of the source/drain metal layer to expose a portion of the silicon layers of the TFT body, but leaving regions of sacrificial source/drain metal over the photodiode islands, and forming a back channel in the TFT body by a back channel etch step. The method further includes then removing the sacrificial regions of source/drain metal from above the photodiode islands, and depositing a passivation layer over the entire exposed surface of the array.
摘要:
In an imager having an array of light-sensitive elements and employing striped common electrodes, exposed edges of preimidized polyimide layers above the light-sensitive imaging elements are sealed with the material of the common electrode (e.g., indium tin oxide). Similarly, exposed preimidized polyimide edges in electrical contacts for the array and bridge members electrically coupling adjacent light-sensitive imaging elements are also sealed with the material of the common electrode.
摘要:
In an imager having an array of light-sensitive elements and employing striped common electrodes, exposed edges of preimidized polyimide layers above the light-sensitive imaging elements are sealed with the material of the common electrode (e.g., indium tin oxide). Similarly, exposed preimidized polyimide edges in electrical contacts for the array and bridge members electrically coupling adjacent light-sensitive imaging elements are also sealed with the material of the common electrode.
摘要:
A method of forming a contact for a photosensitive element of a photosensitive imager including a common electrode separated from a bottom contact by intervening layers of an SiOx transistor passivation layer over the bottom contact and an SiNx diode passivation layer over the transistor passivation layer. Controlled etching through the passivation layers exposes but does not damage the thin film transistor passivation layer extending in regions beyond the common electrode, and also improves adherence of a protective gasket in such regions. The contact pad formed in this process has a layer of diode passivation material and a layer of transistor passivation material disposed between the upper common electrode material layer and the underlying source and drain electrode material layer, with a via provided having smooth and sloped sidewalls over which the common electrode material extends to provide electrical contact between the common electrode material layer and the source and drain electrode material layer.
摘要:
Contact pads for providing external electrical connection to components on a radiation imager having a photosensor array include a body of the material utilized for fabrication of the photosensors with an indium tin oxide (ITO) top layer disposed over the photosensor material to provide a contact region. A metal contact surface can also be disposed over the ITO. A barrier dielectric material is further disposed over portions of the contact pad.
摘要:
A solid state imager is provided that comprises an imaging array of gated photodiodes. The imager comprises a plurality of photosensor pixels arranged in a pixel array, and each of the photosensor pixels includes a photodiode having a sidewall, the sidewall having a gate dielectric layer disposed thereon, and a field plate disposed around the photodiode body. The field plate comprises amorphous silicon disposed on the gate dielectric layer and extends substantially completely around the sidewall of said photodiode. The field plate is electrically coupled to the common electrode of the imaging array so that the field plate creates an electric field around the photodiode body in correspondence with the potential of said common electrode. A method of fabricating the gated photodiode array is also provided.