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An ionizing radiation-tolerant CMOS active pixel sensor (APS) image sensor test chip was designed employing the physical design techniques of enclosed geometry and P-channel guard rings. The test chip was fabricated in a standard 0.35-[micro]m CMOS process that has a gate-oxide thickness of 7.0 nm. It was irradiated by a [gamma]-ray source up to a total ionizing radiation dose level of approximately 30 Mrd (Si) and was still functional. The most pronounced effect was the increase of dark current, which was linear with total dose level. The rate of dark current increase was about 1 to 2 pA/[cm.sup.2]/Krd (Si), depending on the design of the pixel. The results demonstrate that CMOS APS image sensors can be designed to be ionizing radiation tolerant to total dose levels up to 30 Mrd (Si). The fabrication process is standard CMOS, yielding a significant cost advantage over specialized radiation hard processes. Index Terms--Active pixel sensor, CMOS active pixel sensor, CMOS APS, dark current, image sensor, imager, ionizing radiation, ionizing radiation-induced dark current, ionizing radiation-tolerant CMOS APS, radiation hard, radiation tolerant.

Rapid progresses in computers, telecommunication, and consumer electronics research have stimulated the emergence of powerful multimedia systems that will have profound impacts on scientific, industrial, business endeavors, and even our daily lives. Continuous advances in deep-submicron microelectronic fabrication technologies have made possible the integration of millions of transistors on a single silicon microchip. However, one of the anticipated major technological breakthroughs will be the efficient and reliable use of optical links to increase the communication bandwidth and quality of electronic systems. Optical links can be used not only at the machine-to-machine level, but also at the board-to-board and chip-to-chip levels. The architecture, design, and associated measurement results are presented regarding the use of optical interconnections to enhance desktop multimedia computing systems. Index Terms - Computer graphics, multimedia, multiprocessing, optical interconnection, parallel processing.

A [G.sub.m] C-style state constrained neuron (SCN) model for the design of processors in analog recurrent neural networks such as Hopfield neural networks, cellular nonlinear networks for combinatorial optimization is described. The unconstrained neurons which have the free state variable, could be stable at any arbitrary point in the solution space or trapped by un-intentional effects. These may introduce errors. For the unconstrained network, the solution could be different from the expected one due to the discrepancy in the energy function of the network and the objective function to be optimized. In addition, if the state variable is limited by some neighboring saturated transistors, un-desirable results may be obtained. [G.sub.m] C-style SCN model can ensure the convergence of the network and avoid discrepancy between the energy function of the network and the objective function. The state resistor is also eliminated in the [G.sub.m] C model so that high cell-density can be achieved. Simulation results show that the proposed model is effective in significantly reducing optimization error.

The paper describes results of crosstalk investigations and microlens (µ-lens) scan experiments in a color CMOS image sensor with active pixel structure [1]. The investigation of optical and electrical crosstalk was made on 7.8- and 5.6-µm pixels by using samples with continuos shift of color filter (CF) and µ-lens across the array. As a result of this investigation, the distribution of sensitivity inside a pixel has been determined. By using minimum crosstalk criteria, the optimum parameters of the µ-lens manufacturing process and optimum position of the µ-lens was determined. The paper presents color maps of pixel sensitivity and crosstalk criteria as well as snapshots illustrating sensitivity distribution and collection area. The paper presents spectral characteristics measured at different relative apertures (f-number) as well. The quantitative analysis of spectral responses allowed us to determine the contribution of each component to the overall crosstalk. [ABSTRACT FROM AUTHOR]