CCDイメージセンサにおける光電変換特性の非線形性 [in Japanese] A Nonlinearity Consideration on Photoelectric Conversion Characteristics in CCD Image Sensor [in Japanese]
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The photodiodes with a vertical overflow drain are generally used in CCD image sensors. During the charge storage time, the minimum potential point in the barrier region moves toward the photo-diode surface. Almost incident light of short wavelength is absorbed within the surface side shallower than the minimum potential point. Therefore, nonlinearity between the incident light intensity and the output signal does not occur. However, for long wavelength light, since considerable light absorption takes place around the minimum potential point, the nonlinearity arises. The measured nonlinearity for the red incident light was about 5%. The nonlinearity obtained by the calculation coincided qualitatively with that of the measurements. Also, the calculation made clear that the wider barrier width, the low barrier impurity concentration, the low substrate impurity concentration, narrow storage region width, and low substrate bias enhance the nonlinearity.
- The Journal of the Institute of Electrical Engineers of Japan
The Journal of the Institute of Electrical Engineers of Japan 119(11), 604-610, 1999-11
The Institute of Electrical Engineers of Japan