S. Kawai et al., PHOTO RESPONSE ANALYSIS IN CCD IMAGE SENSORS WITH A VOD STRUCTURE, I.E.E.E. transactions on electron devices, 42(4), 1995, pp. 652-655
Photo response in CCD image sensors with Vertical-Overflow-Drain (VOD)
was analyzed in an attempt to discover a way to lessen the photo resp
onse rise that accompanies increasing incident light intensity in the
saturation region. A photo response analysis based on transistor I-V c
haracteristics revealed that the extent of rise in the saturation regi
on is uniquely determined by the non-ideality factor and temperature.
Calculating of the non-ideality factor and its dependence on P-well im
purity concentration and layer thickness further revealed that fabrica
tion of P-wells with lower impurity concentrations and thicker layers
would be effective in suppressing photo response rise.