Trench CCD image sensor

The authors describe and present simulation data on the device structure, process flow, and operation of the Trench CCD (charge coupled device), which is being developed to increase the resolution of solid-state image sensors. The device provides larger dynamic range, higher sensitivity, and no image lag together with great packing density. A charge transfer channel formed around a trench eliminates the problem of insufficient dynamic range, which restricts the resolution. Because the Trench CCD occupies a small percentage of the total pixel area, the aperture area is increased, leading to improved sensitivity. Trench fabrication technology is used in dynamic RAM production; hence, further refinements can be expected to enable improvement of CCD image sensor performance parameters other than dynamic range. These features allow the development of a Trench CCD with 2 million pixels for 2/3-in and smaller optical systems, bringing a practical consumer HDTV (high-definition TV) camera closer to reality