Abstract: Back-illuminated, thin photodiode arrays with trench isolation. The trenches are formed on one or both sides of a substrate, and after doping the sides of the trenches, are filled to provide electrical isolation between adjacent photodiodes. Various embodiments of the photodiode arrays and methods of forming such arrays are disclosed.

Abstract: Structures and methods to improve the crosstalk between adjacent pixels of back-illuminated photodiode arrays on a substrate having first and second surfaces, including providing a first matrix of regions of a first conductivity type of a higher conductivity than the substrate extending into the substrate from the first surface and surrounding each photodiode of the array, and providing a second matrix of regions of a first conductivity type of a higher conductivity than the substrate extending into the substrate from the second surface, the second matrix being a mirror image of and aligned with the first matrix, the matrices extending into the substrate less than one half the thickness of the substrate so as to not touch each other. The methods and corresponding structures may be applied to p/n diodes, pin diodes, avalanche photodiodes, photoconductive cells (no p-n junction at all), or similar photosensitive device arrays.

Abstract: Ultra thin photodiode array structures and fabrication methods are disclosed. The back illuminated or front illuminated photodiode arrays have the active portion fabricated in a semiconductor layer which may be bonded to a supporting substrate layer. The active portion of semiconductor layer may comprise epitaxially grown layer. The isolation regions between pixels of an array may span the epitaxial layer and a semiconductor layer. Electrical contacts to the diodes are made through the bonded substrate or a portion of active layer. Methods of fabrication include steps to form a photodiode array of this type as well as steps to bond this array to supporting substrates. In some embodiments, supporting substrates are temporarily bonded for support of the methods of processing.

Abstract: A system for tracking entities at a site comprises a mesh of radio frequency identification (RFID) tags. Each of the tracked entities, which may move about the site, is associated with and attached to a portable RFID tag. Each RFID tag is at least periodically caused to transmit a signal that includes an identification of the RFID tag. The signal is received by other RFID tags that are within range, which determine a location indicative parameter. Some of the RFID tags receiving the signal are fixed at predefined locations. Specific fixed RFID tags are designated as controller nodes. Data comprising an identification of the RFID tag receiving a signal, the location indicative parameter, and the identification of the portable RFID tag transmitting the signal are communicated to a location engine server, which processes the data to determine at least a relative position of the portable RFID tags on the site.

Abstract: Back-illuminated silicon photomultipliers having a substrate of a first conductivity type having front and back sides, a matrix of regions of a second conductivity type in the substrate, a matrix of regions of the first conductivity type under the matrix of regions of the second conductivity type and adjacent the back side of the substrate, with the bottom of the matrix of regions of the second conductivity type forming a p/n junction with the substrate or a matrix of regions of the second conductivity type, the matrix of regions of the first conductivity type having a higher conductivity than the substrate, a common anode formed by a uniform layer of the first conductivity type of higher conductivity than the substrate on the back side of the substrate. Preferably a plurality of trenches filed with an opaque material are provided in the back side of the substrate, the substrate preferably having a thickness of less than approximately 150 um.

Abstract: This invention describes an imaging system based on an array of semiconductor photosensitive elements with isolating structure between elements (pixels) of the array. The isolated pixels of the array may be photodiodes and they provide excellent imaging capabilities that are important for many applications. The isolated photosensitive pixels may be comprised also by photoconductors, avalanche photodiodes, photosensitive IC, or other similar solid-state devices. The fields of possible application include but are not limited to the detector modules for homeland security, medical imaging systems (CT, SPECT, and PET including), fundamental and applied research, etc.

Abstract: Structures and methods to improve the crosstalk between adjacent pixels of back-illuminated photodiode arrays on a substrate having first and second surfaces, including providing a first matrix of regions of a first conductivity type of a higher conductivity than the substrate extending into the substrate from the first surface and surrounding each photodiode of the array, and providing a second matrix of regions of a first conductivity type of a higher conductivity than the substrate extending into the substrate from the second surface, the second matrix being a mirror image of and aligned with the first matrix, the matrices extending into the substrate less than one half the thickness of the substrate so as to not touch each other. The methods and corresponding structures may be applied to p/n diodes, pin diodes, avalanche photodiodes, photoconductive cells (no p-n junction at all), or similar photosensitive device arrays.

Abstract: A method of analyzing suspended solids, particularly in flowing liquids, in which a plurality of light sources and photodetectors are employed in predetermined arrangement to provide a relatively short light path and a relatively long light path for each photodetector, with the light sources being actuated in predetermined off-on sequence, to provide corresponding periods of illumination from each light source and intermediate periods of no illumination, with the no illumination value representing ambient light, and so combining the respective light values so obtained to provide values representing not only the suspended solid content but also comparison values indicating the presence of failures of the respective light sources and photodetectors, and apparatus for practicing the method.

Abstract: A device for measuring particles in a liquid, utilizing a light source for the illumination of two detectors, one through a relatively short distance and the other through a relatively long distance, with liquid to be measured passing between the light source and the two detectors. A reference signal produced by the first cell is supplied to an amplifier and indicator, and a measurement signal produced by the second detector is supplied to the amplifier and indicator, with such amplifier and indicator producing a visual indication of the concentration of particles suspended in the liquid. The two detectors and light source are contained in a small housing, remote from the amplifier and indicator, and connected to it by a flexible cable.