A 1/2-inch 1.3 MPixel progressive-scan CCD image sensor employing 0.25 /spl mu/m gap single-layer poly-Si electrodes

A 1/2-inch 1.3 Mpixel progressive-scan interline-transfer charge-coupled device (IT-CCD) image sensor for low-power high-sensitivity digital cameras uses 0.25 /spl mu/m-gap single-layer poly-Si for CCD electrodes to reduce drive voltage and gate overlap capacitance. The device achieved a low driving voltage (2.1 V) on a horizontal CCD at a frequency of 24.5 MHz. Pixel layout and a self-aligned photodiode structure achieve a progressive-scan pixel with controlled photodiode readout characteristics. An output 3-stage source follower amplifier with new multi-oxide transistors, whose gate insulator thickness is thinner than that of a CCD register, has 17% higher gain than that obtained using a conventional amplifier. As a result, 100 mW and -90 dB smear are obtained. The fabrication process steps are reduced to 70% of those with conventional 3-layer poly-Si electrodes.