Win-Chyi Chang

The pinned photodiode for an interline-transfer CCD image sensor

A pinned photodiode has been developed for use in an interline-transfer CCD. This photoelement has excellent blue response and high charge capacity. Both modeling and experimental results will be presented, including process considerations necessary to avoid unwanted barriers at the diode/transfer-gate edge.

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.

A large area 1.3-megapixel full-frame CCD image sensor with a lateral-overflow drain and a transparent gate electrode

A large-area, 1.3 million pixel, full-frame CCD (charge coupled device) image sensor has been developed that incorporates both a lateral-overflow drain (LOD) for antiblooming control and a transparent indium-tin oxide (ITO) gate electrode for increased photosensitivity. The LOD offers high responsivity, extremely linear photoresponse, and ultrahigh optical overload protection. The replacement of one polysilicon phase with ITO increases the quantum efficiency at 400 nm to 15.8% from the 1.5% for the standard double polysilicon gate electrode process. The LOD design allows for antiblooming suppression in excess of 43000 times the saturation signal while maintaining better than 1% nonlinearity.<<ETX>>

3.2-million-pixel full-frame true 2Φ CCD image sensor incorporating transparent gate technology

This paper describes the performance of an advanced high- resolution full-frame architecture CCD imaging device for use in scientific, medical and other high-performance monochromatic digital still imaging applications. Of particular interest is the replacement of the polysilicon 2nd gate electrode with that of a more spectrally transparent material thereby dramatically improving device sensitivity. This has been achieved without compromising performance in other areas such as dark current, noise, transfer efficiency and, most importantly, yield.

Four-million-pixel CCD image sensor

An ultra high resolution image sensor has been developed for industrial and scientific applications. The ultra high resolution sensor is a full-frame CCD sensor, consisting of 2048 x 2048 pixels, and its image area measures 18.43 mm x 18.43 mm. The pixel size is 9 x 9 microns. The sensor has dual readout registers to increase the data rate and can be operated in the single or dual readout register mode. The architecture of this imager is suitable for accumulation mode operation, which results in a very low dark current of 10 pA/sq cm at room temperature.

A four-million pixel CCD image sensor

The authors have developed an ultra-high-resolution, full-frame CCD imager of 2048*2048 pixels. The pixel size is 9 mu m*9 mu m. The sensor has dual readout registers to increase the data rate. It is designed for a horizontal clock rate of 20 MHz. With the dual line readout mode, it takes 114 ms to read a frame. The experimental device has less than 0.5 nA/cm/sup 2/ dark current at room temperature, corresponding to about 25 electrons of dark shot noise at 200 ms frame time, including both integration and read time. The output amplifier, made of a two-stage source follower, has a sensitivity of 10 mV per electron. With correlated double sampling, the output amplifier contributes about 10 noise electrons at the 20 MHz data rate. Thus, the dark shot noise is the dominant noise component unless the imager is cooled. The charge capacity of the CCD is 85000 electrons, giving a dynamic range of 3000. A charge transfer efficiency of 0.99999 has been observed.<<ETX>>An ultra-high resolution image sensor was developed for industrial and scientific applications. The imager is a full-frame CCD sensor, consisting of 2048 × 2048 pixels, and its image area measures 18.43 mm × 18.43 mm. The pixel size is 9 microns × 9 microns. The sensor has dual readout registers to increase the data rate. The sensor could be operated in the single or dual readout register mode depending on the users frame rate requirements and the data capture system. The architecture of this imager is suitable for accumulation mode operation, which results in low dark current of less than 10 pA/cm2 at room temperature. The charge transfer efficiency is 0.99999 for horizontal clock rate up to 20 MHz.

Monte Carlo Simulation of the Photoelectron Crosstalk in Silicon Imaging Devices

The Monte Carlo method is used to evaluate the extent of the crosstalk in solid-state imagers. The calculations are performed in three dimensions and are in excellent agreement with experiment. The Monte Carlo method is used because it handles adjacent regions that either collect or reflect minority carriers.

Six-million-pixel full-frame true 2-f CCD image sensor incorporating transparent gate technology and optional antiblooming protection

This paper describes the performance of an advanced high- resolution full-frame architecture CCD imaging device for use in scientific, medical, and other high performance monochromatic digital still imaging applications. Of particular interest is the replacement of the polysilicon second gate electrode with that of a more spectrally transparent material, thereby dramatically improving device sensitivity. This has been achieved without compromising performance in other areas such as dark current, noise, transfer efficiency and, most importantly, yield. Devices have also been produced with and without antiblooming protection depending on an applications primary need for sensitivity or control of over-exposure conditions.

1536 x 1024 CCD image sensor

High-resolution solid-state image sensors have become readily available due to continuing advances in VLSI technology. The authors have developed a 1.6 megapixel full-frame CCD image sensor (KAF-1600) with a 3:2 aspect ratio to meet industrial and scientific applications. The high-resolution sensor, measuring 1.55 cm X 1.0 cm, consists of 1536 X 1024 pixels. The pixel size is 9 microns X 9 microns. The sensor has a single-readout register with the capability of a 2-to-1 line charge summing. The architecture and results of the megapixel image sensor are presented.