Abstract: A radiation imager includes a photosensor array having a plurality of individually addressable pixels, each pixel having a photosensor island and an associated thin film transistor (TFT) disposed to selectively electrically couple the photosensor island to a predetermined address line. In each pixel a single common passivation layer is disposed over the TFT and the photosensor island such that the passivation layer is adjacent to both the outer surfaces of the TFT and portions of the photosensor island. In a method of fabricating a photosensor array as described above, after depositon of a source-drain metal layer, the layer is left unpatterned until after the photosensor island has been formed. In the formation of the photosensor island the source-drain metal layer serves as an etch stop to protect the TFT. Following formation of the photosensor island, the source-drain metal layer is patterned to form source and drain electrodes and fabrication of the TFT is completed.

Abstract: A solid state radiation imager includes a photosensor array having a plurality of pixels disposed on a substrate, each pixel having a respective photosensor coupled to a thin film transistor (TFT). The photosensor array further includes an opaque passivation layer that is disposed over non-photodiode areas of the photosensor array, including the TFT and address lines in the array. The opaque passivation layer has an absorbance that is greater than 1, and typically that is greater than 2. The opaque passivation layer further is typically made of a thermally stable polymer mixed with a light absorbing material such as an organic dye (e.g., Sudan Black B), carbon black, or graphite.

Abstract: A solid state radiation imager pixel having a thin film transistor (TFT) coupled to a photodiode in which the photodiode and the TFT each comprise a common dielectric layer, that is, a single dielectric layer that extends across the pixel and that has a gate dielectric layer portion and a photodiode body passivation portion. The common dielectric layer comprises a monolithic dielectric material such as silicon nitride or silicon oxide. Further, the bottom electrode of the photosensor body and the gate electrode are each disposed on a common surface of the substrate and comprise the same conductive material, the conductive material having been deposited on the pixel in the same deposition process. The source and drain electrodes and the common contact electrode for the photodiode each comprises the same source/drain metal conductive material, the conductive material having been deposited on the pixel in the same deposition process.

Abstract: A solid state radiation imager pixel having a thin film transistor (TFT) coupled to a photodiode in which the photodiode and the TFT each comprise a common dielectric layer, that is, a single dielectric layer that extends across the pixel and that has a gate dielectric layer portion and a photodiode body passivation portion. The common dielectric layer comprises a monolithic dielectric material such as silicon nitride or silicon oxide. Further, the bottom electrode of the photosensor body and the gate electrode are each disposed on a common surface of the substrate and comprise the same conductive material, the conductive material having been deposited on the pixel in the same deposition process. The source and drain electrodes and the common contact electrode for the photodiode each comprises the same source/drain metal conductive material, the conductive material having been deposited on the pixel in the same deposition process.

Abstract: A radiation imager includes a photosensor array having a plurality of individually addressable pixels, each pixel having a photosensor island and an associated thin film transistor (TFT) disposed to selectively electrically couple the photosensor island to a predetermined address line. In each pixel a single common passivation layer is disposed over the TFT and the photosensor island such that the passivation layer is adjacent to both the outer surfaces of the TFT and portions of the photosensor island. In a method of fabricating a photosensor array as described above, after depositon of a source-drain metal layer, the layer is left unpatterned until after the photosensor island has been formed. In the formation of the photosensor island the source-drain metal layer serves as an etch stop to protect the TFT. Following formation of the photosensor island, the source-drain metal layer is patterned to form source and drain electrodes and fabrication of the TFT is completed.

Abstract: Solid state photodetectors having amorphous silicon photodiode bodies with sloped sidewalls allowing for deposition of high integrity conformal layers thereover are produced by etching the amorphous silicon in a mostly anisotropic etchant in a reactive ion etcher in which the pressure of the etchant is controlled. A photoresist mask having sloped sidewalls is formed over the amorphous silicon to be etched and the pressure of the etchant is selected to produce the desired slope of the sidewall in the photodetector body; at lower pressures a smaller slope is produced in the silicon and at higher pressures a steeper slope is produced in the silicon.

Abstract: A method of fabricating a thin film transistor (TFT) including the steps of forming a gate conductor on a substrate; depositing a gate dielectric layer over the gate conductor; depositing a layer of amorphous silicon over the gate dielectric layer; treating the exposed surface of the amorphous silicon with a hydrogen plasma; depositing a layer of n+ doped silicon over the treated amorphous silicon surface such that an interface is formed between the amorphous silicon and the n+ doped layer that has relatively low contact resistance; depositing a layer of source/drain metallization over the n+ doped layer; and patterning the source/drain metallization and portions of the underlying n+ doped layer to form source and drain electrodes. The TFT material layers are preferably deposited by plasma enhanced chemical vapor deposition.

Abstract: Solid state photodetectors having amorphous silicon photodiode bodies with sloped sidewalls allowing for deposition of high integrity conformal layers thereover are produced by etching the amorphous silicon in a mostly anisotropic etchant in a reactive ion etcher in which the pressure of the etchant is controlled. A photoresist mask having sloped sidewalls is formed over the amorphous silicon to be etched and the pressure of the etchant is selected to produce the desired slope of the sidewall in the photodetector body; at lower pressures a smaller slope is produced in the silicon and at higher pressures a steeper slope is produced in the silicon.