A 1/3-inch 1.3M pixel single-layer electrode CCD with a high-frame-rate skip mode

A 1/3-inch 1.3M pixel interline-transfer charge-coupled-device (IT-CCD) image sensor is described for digital camera applications. A 0.25 /spl mu/m-gap single-layer poly-Si is used for the CCD electrodes. The vertical CCD (V-CCD) of the image sensor has ten-phase metal wiring to enable various charge-transfer modes. We have now developed and tested a high-frame-rate skip mode (75 frame/s) and an advanced 3:1 interlaced-scan mode. We developed a method of separately implanting boron ions for the V-CCD and horizontal CCD (H-CCD) in single-layer electrode CCDs with small pixels, to maintain a high charge-transfer efficiency. Furthermore, reducing the pixel size degrades the light-gathering capability of the on-chip microlenses, reducing the sensitivity for a given camera-iris aperture (f number). A new thin-flattened-layer microlens improved the sensitivity of the device. At an f number of 1.4, for example, there was an 18% increase in sensitivity.