More complete charge transfer is achieved in a CMOS or CCD imager by reducing
the spacing in the gaps between gates in each pixel cell, and/or by providing a
lightly doped region between adjacent gates in each pixel cell, and particularly
at least between the charge collecting gate and the gate downstream to the charge
collecting gate. To reduce the gaps between gates, an insulator cap with spacers
on its sidewalls is formed for each gate over a conductive layer. The gates are
then etched from the conductive layer using the insulator caps and spacers as hard
masks, enabling the gates to be formed significantly closer together than previously
possible, which, in turn increases charge transfer efficiency. By providing a lightly
doped region on between adjacent gates, a more complete charge transfer is effected
from the charge collecting gate.