Fundamental Study of Complementary Metal Oxide Semiconductor Image Sensor for Three-Dimensional Image Processing System

In this paper, we describe a fundamental study of a complementary metal oxide semiconductor (CMOS) image sensor for a three-dimensional (3D) image-processing system. We proposed a pixel circuit with correlated double sampling (CDS) and high-speed image capturing for high-speed image processing. The CDS and high-speed image-capture circuit should be realized simultaneously to allow high-speed image processing. The pixel circuit can realize CDS and high-speed image-capture functions simultaneously. The CDS and high-speed image capturing are realized by using a pixel sample hold capacitor and shared coupling capacitor. Appending extra capacitors causes the pixel circuit size to become large in the two-dimensional (2D) CMOS image sensor. We proposed a 3D CMOS image sensor that can reduce the pixel circuit size and the electrical wiring length and increase the fill factor, even with CDS and high-speed image capturing. Therefore, small, high-speed parallel-processing systems can be realized by using our 3D CMOS image sensor. We fabricated the prototype 2D pixel circuit with CDS and high-speed image capturing. The prototype pixel circuit is successfully implemented in the simultaneous function. We believe the proposed pixel circuit is very effective for 3D CMOS image processing. (c) 2009 The Japan Society of Applied Physics