David Newell Nichols

Latch-up and image crosstalk suppression by internal gettering

Internal gettering can be used to reduce crosstalk in imagers and latch-up susceptibility in CMOS circuits. The internal gettering process forms defects in the bulk of the silicon wafers that are effective recombination sites for minority carriers in the substrate. Experimental and theoretical results are presented for the crosstalk reduction obtained in an area imager. Also, the current gain β of the parasitic lateral n-p-n transistors formed in the substrate in CMOS circuits was considerably lower for the internally gettered wafers. The trigger current needed to initiate latch-up in the n-p-n-p structures increased as 1/β, in accordance with the theory. A Monte Carlo method was developed to calculate the expected lateral transistor current gain. The calculated βs are in excellent agreement with the measured values.

A 1-Megapixel, progressive-scan image sensor with antiblooming control and lag-free operation

A 1024-pixel*1024-pixel interline charge-coupled device (IL CCD) image sensor has been developed. It incorporates antiblooming and electronic exposure control while eliminating lag and obtaining a high responsivity. The novel features of this device include a noninterlaced, or progressive-scan, architecture and dual-horizontal registers that can be used to clock out the image area by one or two lines at a time. These features make it well suited for applications demanding high-resolution-image capture from a single, high-speed scan. The progressive-scan architecture of this device covers the same resolution in an electronic-camera application as that of a 2-million-element, interlaced device. >

A 1.4 million element, full frame CCD image sensor with vertical overflow drain for anti-blooming and low color crosstalk

Blooming and color crosstalk must be greatly suppressed in solid-state image sensors for nearly all imaging applications. A vertical overflow drain has been developed for a 1.4 megapixel image sensor for blooming suppression and low color crosstalk. The overflow drain is formed using a uniform flat p-well. This paper describes the modeling, fabrication, and experimental data associated with implementing vertical overflow in this device.

Latch-up and image crosstalk suppression by internal gettering [in CMOS]

Internal gettering can be used to reduce crosstalk in imagers and latch-up susceptibility in CMOS circuits. The internal gettering process forms defects in the bulk of the silicon wafers that are effective recombination sites for minority carriers in the substrate. Experimental and theoretical results are presented for the crosstalk reduction obtained in an area imager. Also, the current gain β of the parasitic lateral n-p-n transistors formed in the substrate in CMOS circuits was considerably lower for the internally gettered wafers. The trigger current needed to initiate latch-up in the n-p-n-p structures increased as 1/β, in accordance with the theory. A Monte Carlo method was developed to calculate the expected lateral transistor current gain. The calculated βs are in excellent agreement with the measured values.

31 Mp and 39 Mp full-frame CCD image sensors with improved charge capacity and angle response

This paper describes the design and performance of two new high-resolution full-frame architecture CCD imaging devices for use in professional color, digital still-imaging applications. These devices are made using 6.8 μm pixels and contain a dual-split HCCD register with two outputs to increase frame rate. The KODAK KAF-31600 Image Sensor (31 Mp) is designed with microlenses to maximize sensitivity, whereas the KODAK KAF-39000 Image Sensor (39 Mp) is designed without microlenses to maximize incident light-angle response. Of particular interest is the implementation of an under-the-field oxide (UFOX) lateral overflow drain (LOD) and thin light shield process technologies. The new UFOX LOD structure forms the LOD under the thick-field oxide that eliminates a breakdown condition, allowing much higher LOD doping levels to be used. The net result is that the LOD may be scaled to smaller dimensions, thereby enabling larger charge capacities without compromising blooming control. The thin light shield process utilizes only the TiW portion of the TiW/Al metal bilayer to form the pixel aperture. This reduces the overall stack height that helps improve angle response (for pixels using microlenses) or critical crosstalk angles (for pixels without microlenses).

High‐resolution interline image sensors using two‐phase CCD technology

Two interline, 30 frames/second, high‐resolution image sensors are described that use two‐phase charge coupled device (CCD) technology. One is a two‐megapixel, interlaced high‐definition television, sensor, and the other is a 1‐megapixel, progressive‐scan sensor for machine vision applications. These sensors include features such as dual‐horizontal CCD readout, antiblooming protection, electronic shutter capability, low smear, and no lag.©1994 John Wiley & Sons Inc

1-megapixel IL-CCD image sensor with a progressive scan, antiblooming control, and lag-free operation

A 1024 x 1024 pixel, interline charge-coupled device (IL CCD) image sensor has been developed that incorporates antiblooming and electronic exposure control while eliminating lag and obtaining a high responsivity. Of the novel features of this device are its noninterlaced, or progressive-scan architecture and dual-horizontal registers that can be used to clock out the image area by one or two lines at a time. These features make it well suited for applications demanding high-resolution-image capture from a single, high-speed scan.

New 5.5 μm Interline Transfer CCD Platform for Applied Imaging Markets

A new 5.5 &mgr;m pixel interline transfer CCD technology platform has been developed that offers significant improvements in performance while retaining the dynamic range, quantum efficiency, and responsivity available from the previous generation 7.4 µm pixel. Smear has been reduced to -100 dB, and a new quad-output architecture increases the maximum frame rate up to 120 fps for a 1 MPix sensor. This technology is now being deployed across a family of image sensors that share a common package and pin-out, facilitating faster camera design and product commercialization.

Recent advances in high-throughput QCL-based infrared microspectral imaging (Conference Presentation)

The field of infrared spectral imaging and microscopy is advancing rapidly due in large measure to the recent commercialization of the first high-throughput, high-spatial-definition quantum cascade laser (QCL) microscope. Having speed, resolution and noise performance advantages while also eliminating the need for cryogenic cooling, its introduction has established a clear path to translating the well-established diagnostic capability of infrared spectroscopy into clinical and pre-clinical histology, cytology and hematology workflows. Demand for even higher throughput while maintaining high-spectral fidelity and low-noise performance continues to drive innovation in QCL-based spectral imaging instrumentation. In this talk, we will present for the first time, recent technological advances in tunable QCL photonics which have led to an additional 10X enhancement in spectral image data collection speed while preserving the high spectral fidelity and SNR exhibited by the first generation of QCL microscopes. This new approach continues to leverage the benefits of uncooled microbolometer focal plane array cameras, which we find to be essential for ensuring both reproducibility of data across instruments and achieving the high-reliability needed in clinical applications. We will discuss the physics underlying these technological advancements as well as the new biomedical applications these advancements are enabling, including automated whole-slide infrared chemical imaging on clinically relevant timescales.

A lag-free 1024*1024 progressive scan interline CCD image sensor with antiblooming and exposure control

A 1024*1024 IL CCD (charge coupled device) image sensor has been developed that incorporates antiblooming and electronic exposure control while eliminating lag and obtaining a high responsivity. The incorporation of the antiblooming structure and electronic exposure control has been achieved without sacrificing other important device characteristics such as lag, smear, photoresponse linearity, and sensitivity. The progressive-scan architecture of this device offers the same resolution in an electronic-camera application as that of a two-million element, interlaced device. A noninterlaced scan with dual-horizontal registers makes it well suited for high-speed, machine vision applications.<<ETX>>