Radiation Detector with Isolated Pixels Photosensitive Array for CT and Other Imaging Applications

A radiation detector array comprising:

• a radiation sensitive surface which converts received radiation into photons of light;
• a photodiode array that comprises a semiconductor substrate of a first conductivity type having first and second surfaces, the second, back surface being free of electrical contacts in optical communication with the radiation sensitive surface, and which photodiode array generates electrical signals responsive to the photons of light generated by the radiation sensitive surface, the second surface having a layer of the first conductivity type having a greater conductivity than the semiconductor substrate;
• a matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending from the first surface of the semiconductor substrate to the layer of the first conductivity type having a greater conductivity than the said semiconductor substrate, wherein the entire matrix regions are semiconductor doped regions;
• a plurality of regions of the second conductivity type interspersed within the matrix of regions of the first conductivity type and not extending to the layer of the first conductivity type on the second surface of the semiconductor substrate;
• a plurality of contacts on the first surface for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• and which has its contacts arranged on a first, top surface opposite the second, back surface, and a support substrate supporting the photodiode, the support substrate configured to provide an electrical path from the contacts on the first surface of the photodiode through the support substrate.

A radiation detector array comprising:

• a radiation sensitive surface which converts received radiation into photons of light;
• a photodiode array that comprises a semiconductor substrate of a first conductivity type having first and second surfaces, the second, back surface in optical communication with the radiation sensitive surface, which generates electrical signals responsive to the photons of light generated by the radiation sensitive surface, the second surface having a layer of the first conductivity type having a greater conductivity than the said semiconductor substrate;
• a first matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending into the semiconductor substrate from the first surface of the said semiconductor substrate;
• a second matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending into the said semiconductor substrate from the second surface of the semiconductor substrate and aligned with the first matrix, the first and second matrices not extending into the said semiconductor substrate to touch each other;
• a plurality of regions of the second conductivity type interspersed within the first matrix of regions of the first conductivity type on the first surface of the semiconductor substrate and not extending to the layer of the first conductivity type on the second surface of the said semiconductor substrate;
• a plurality of contacts on the first surface of a semiconductor substrate for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• and which has its signal contacts arranged on a first, top surface opposite the second, back surface of the semiconductor substrate;
• and
• a support substrate supporting the photodiode, the support substrate configured to provide an electrical path from the contacts on the first surface of the photodiode through the support substrate.

A method comprising:

• illuminating a radiation sensitive surface with x-rays;
• converting the x-rays illuminating the radiation sensitive surface into light;
• producing an electrical signal proportional to the converted light with a photodiode array wherein said photodiode array comprises a semiconductor substrate of a first conductivity type having first and second surfaces;
• the second surface having a layer of the first conductivity type having a greater conductivity than the semiconductor substrate;
• a matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending from the first surface of the said semiconductor substrate to the layer of the first conductivity type having a greater conductivity than the semiconductor substrate, wherein the entire matrix regions are semiconductor doped regions;
• a plurality of regions of the second conductivity type interspersed within the matrix of regions of the first conductivity type and not extending to the layer of the first conductivity type on the second surface of the semiconductor substrate;
• a plurality of contacts on the first surface for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• and,
• communicating the electrical signal through a support substrate to processing circuitry sheltered from the x-rays via a path orthogonal to the radiation sensitive surface.

A method comprising:

• illuminating a radiation sensitive surface with x-rays;
• converting the x-rays illuminating the radiation sensitive surface into light;
• producing an electrical signal proportional to the converted light with a photodiode array wherein said photodiode array comprises a semiconductor substrate of a first conductivity type having first and second surfaces;
• the second surface having a layer of the first conductivity type having a greater conductivity than the semiconductor substrate;
• a first matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending into the said semiconductor substrate from the first surface;
• a second matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending into the said semiconductor substrate from the second surface of the semiconductor substrate and aligned with the first matrix, the first and second matrices not extending into the semiconductor substrate to touch each other;
• a plurality of regions of the second conductivity type interspersed within the first matrix of regions of the first conductivity type on the first surface of the semiconductor substrate and not extending to the layer of the first conductivity type on the second surface of the said semiconductor substrate;
• a plurality of contacts on the first surface for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• and,
• communicating the electrical signal through a support substrate to processing circuitry sheltered from the x-rays via a path orthogonal to the radiation sensitive surface.

A radiation detection system comprising:

• a scintillator block for converting X-rays into light;
• a photo-sensitive device having multiple photo-sensitive elements arrayed upon a semiconductor substrate with isolation surrounding the periphery of each of said multiple elements, wherein said isolation propagates between a first, top surface and a second, back surface of the semiconductor substrate;
• a plurality of contacts on the first surface for making electrical contact to the plurality of photosensitive elements and to the isolation regions;
• communicating the electrical signal through a first support substrate to processing circuitry sheltered from the x-rays via a path orthogonal to the radiation sensitive surface;
• a processing circuitry or readout electronics formed on a chip or second support substrate attached to the first support substrate;
• a switch for selecting a photodiode, from said photodiode array, from which an electrical signal is to be output;
• a data acquisition chip for acquiring data output from said photodiode array selected by said switch;
• and
• means for integrating said scintillator block, said photosensitive device, said support substrates, and said data acquisition, said switch and processing circuitry chip.

A radiation detection system comprising:

• a scintillator block for converting X-rays into light;
• a photodiode array for converting the light into electrical signals wherein said photodiode array comprises a semiconductor substrate of a first conductivity type having first and second surfaces;
• the second surface having a layer of the first conductivity type having a greater conductivity than the semiconductor substrate;
• a matrix of regions of a first conductivity type of a higher conductivity than the semiconductor substrate extending from the first surface of said semiconductor substrate to the layer of the first conductivity type having a greater conductivity than the semiconductor substrate, wherein the entire matrix regions are semiconductor doped regions;
• a plurality of regions of the second conductivity type interspersed within the matrix of regions of the first conductivity type and not extending to the layer of the first conductivity type on the second surface of the semiconductor substrate;
• a plurality of contacts on the first surface for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• communicating the electrical signal through a first support substrate to processing circuitry sheltered from the x-rays via a path orthogonal to the radiation sensitive surface;
• a processing circuitry and readout electronics formed on a chip or second support substrate attached to the first support substrate;
• a switch for selecting a photodiode, from said photodiode array, from which an electrical signal is to be output;
• a data acquisition chip for acquiring data output from said photodiode array selected by said switch;
• and
• means for integrating said scintillator block, said photodiode array, said support substrates for signal communication, and said data acquisition chip and switch.

An imaging system comprising:

• an x-ray radiation source selectively generating a beam of x-ray radiation that traverses an examination region from a multiplicity of directions;
• a radiation detector positioned opposite the examination region from the radiation source, the radiation detector comprising a photo-sensitive device having multiple photo-sensitive elements arrayed upon a semiconductor substrate with isolation surrounding the periphery of each of said multiple elements, wherein said isolation propagates between a first, top surface and a second, back surface of the substrate;
• a plurality of contacts on the first surface of the semiconductor substrate for making electrical contact to the plurality of photosensitive elements and to the isolation regions;
• a scintillation crystal overlaying the photodetector array for converting received x-ray radiation into light, the scintillation crystals being optically coupled to the elements of the photo-sensitive device;
• a support substrate comprising a first support substrate layer disposed parallel to the photo-sensitive array and a second support substrate layer or chip disposed at any angle to and in support of the first support substrate layer;
• and,
• a plurality of contacts and paths below the photo-sensitive array through the substrate, the paths providing electrical connectivity between the photodetectors and signal processing circuitry.

An imaging system comprising:

• an x-ray radiation source selectively generating a beam of x-ray radiation that traverses an examination region from a multiplicity of directions,
• a radiation detector array positioned opposite the examination region from the radiation source, the radiation detector array including a plurality of photodetectors arranged in an array, the photodetector array comprising a semiconductor substrate of a first conductivity type having first and second surfaces, the second surface having a layer of the first conductivity type having a greater conductivity than the substrate, a matrix of regions of a first conductivity type of a higher conductivity than the said semiconductor substrate extending from the first surface of the semiconductor substrate to the layer of the first conductivity type having a greater conductivity than the semiconductor substrate, wherein the entire matrix regions are semiconductor doped regions, a plurality of regions of the second conductivity type interspersed within the matrix of regions of the first conductivity type and not extending to the layer of the first conductivity type on the second surface of the semiconductor substrate, and a plurality of contacts on the first surface for making electrical contact to the matrix of regions of the first conductivity type and the plurality of regions of the second conductivity type;
• a scintillation crystal overlaying the photodetector array for converting received x-ray radiation into light, the scintillation crystals being optically coupled to the primary photodetectors;
• a support substrate comprising a first support substrate layer disposed parallel to the photodetector array and a second support substrate layer or chip disposed at any angle to and in support of the first support substrate layer;
• and,
• a plurality of contacts and paths below the primary photodetector array through the substrate, the paths providing electrical connectivity between the photodetectors and signal processing circuitry.