http://eia.udg.es/%7Eqsalvi/papers/2006-MJ.pdf

Review of CMOS image sensors

Various embodiment include optical and optoelectronic devices and methods of making same. Under one aspect, an optical device includes an integrated circuit having an array of conductive regions, and an optically sensitive material over at least a portion of the integrated circuit and in electrical communication with at least one conductive region of the array of conductive regions. Under another aspect, a film includes a network of fused nanocrystals, the nanocrystals having a core and an outer surface, wherein the core of at least a portion of the fused nanocrystals is in direct physical contact and electrical communication with the core of at least one adjacent fused nanocrystal, and wherein the film has substantially no defect states in the regions where the cores of the nanocrystals are fused. Additional devices and methods are described.

Quantum dot optical devices with enhanced gain and sensitivity and methods of making same

Image sensors in thin film on ASIC (TFA) technology are composed of amorphous silicon (a-Si:H) thin-film detectors on top of crystalline ASIC's. With regard to advanced imaging systems, TFA provides enhanced performance and more flexibility than conventional technologies. Extensive on-chip signal processing is feasible, as well as small pixels for high-resolution imagers. Several prototypes of TFA sensors have been developed, optimized for considerably different applications. This paper focuses on a TFA sensor for automotive vision systems that allows each pixel to adapt its individual sensitivity to the local illumination intensity. By this means, a dynamic range of 120-dB minimum along with high local contrast is achieved. The recent second prototype array consists of 368/spl times/256 pixels with an area of 40/spl times/38 /spl mu/m/sup 2/ each. The ASIC's were fabricated in a 0.7-/spl mu/m CMOS technology, whereupon the a-Si:H thin film was deposited in a plasma-enhanced chemical vapor deposition cluster system.

Design and fabrication of a high-dynamic-range image sensor in TFA technology

-Apart from the ongoing debate about using CMOS active pixel sensors (APS) or CCD imagers for today's consumer and commercial applications the emerging biomedical market presents new opportunities to CMOS APS. Logarithmic response High-Dynamic Range CMOS (HDRC) cells are the preferred photosensitive circuits for building sensors with contrast and not with illumination dominated outputs. Prominent examples addressing distinct issues in life style and health care are the possibilities to restore vision through a sub-retinal CMOS imager implant and to fabricate a low-cost intracorporeal video probe through a miniature CMOS imager. The sub-retinal imager chip presented here is the first implanted into the eye of a blind human patient with partial restoring of vision.

High Dynamic Range CMOS Imager Technologies for Biomedical Applications

Apart from the ongoing debate about using CMOS active pixel sensors (APS) or CCD imagers for today's consumer and commercial applications the emerging biomedical market presents new opportunities to CMOS APS. Logarithmic response high-dynamic range CMOS (HDRC) cells are the preferred photosensitive circuits for building sensors with contrast and not with illumination dominated outputs. Prominent examples addressing distinct issues in life style and health care are the possibilities to restore vision through a sub-retinal CMOS imager implant and to fabricate a low-cost intracorporeal video probe through a miniature CMOS imager. The sub-retinal imager chip presented here is the first implanted into the eye of a blind human patient with partial restoring of vision.

A TFA image sensor consists of an amorphous silicon based multilayer structure on top of a crystalline ASIC. The Multilayer acts as the optical detector, whereas the ASIC performs analog or digital signal processing for each individual pixel. Depending on the operation Mode, the dynamic range of the detector exceeds the performance of conventional CCDs by far. Pixel electronics which is adapted to the requirements of the detector can thereby maximize the dynamic range of the complete sensor array. Crosstalk among adjacent pixels can be eliminated by technological or electronic Means.

Technology and Performance of TFA (Thin Film on ASIC-Sensors

Two different pixel detectors have been fabricated, each of them consisting of an a-Si:H based photodiode layer on top of a crystalline silicon integrated circuit. Both sensors are arranged in a matrix and addressed columnwise, providing parallel readout of the matrix rows or optional random access. One sensor is an a-Si:H detector / x-Si switching transistor combination with 256 x 256 pixels and a pixel size of 100μm x 100μm. The signal transport in the array is examined, demonstrating its capability of very fast information readout. The second sensor, which consists of an array of 32 x 32 pixels on a 5μm PMOS ASIC, performs digital contour extraction. Experimental data on the performance of the intelligent array are also reported.

Thin Film on Asic - A Novel Concept for Intelligent Image Sensors

TFA (Thin Film on ASIC) image sensors consist of an amorphous silicon (a-Si:H) based optical detector on top of an ASIC which performs signal readout or signal processing for each individual pixel. In this paper we present recent prototypes of image sensors in TFA technology. The ASICs have been fabricated in a standard 0.7 /spl mu/m CMOS process, the detector multilayer was deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD).

TFA image sensors: from the one transistor cell to a locally adaptive high dynamic range sensor

Image sensors in TFA (Thin Film on ASIC) technology are composed of amorphous silicon (a-Si:H) thin film detectors on top of crystalline ASICs. A TFA prototype for automotive vision systems is presented which allows each pixel to adapt its individual sensitivity to the local illumination. By this means, a dynamic range of 120 dB minimum along with high local contrast is achieved. The ASICs were fabricated in a 0.7 /spl mu/m CMOS technology.

J. Schulte

Papers

Technology and Performance of TFA (Thin Film on ASIC-Sensors

Thin Film on Asic - A Novel Concept for Intelligent Image Sensors

TFA image sensors: from the one transistor cell to a locally adaptive high dynamic range sensor

Design and fabrication of a high dynamic range image sensor in TFA technology