| 摘要 |
PURPOSE:To pull out electric charges, which are phetoelectrically converted by stray light components, toward the side of the semiconductor substrate so that smears can be decreased, by forming picture element parts, that is, photoelectric conversion elements and vertical electric charge transfer elements on the first identical well small in impurity concentration and depth. CONSTITUTION:A p<->-type well 2 and p-type well 3 are formed on a n-type semiconductor substrate 1. Depth of the p<->-type well 2 is smaller than that of the p-type well 3. Photoelectric conversion elements 4 and vertical electric charge transfer elements 5 are formed on the p<->-type well 2, and horizontal electric charge elements 6 and an output part 7 consisting of MOS transistors are formed on the p-type well 3. In such composition, electric charges generated by incident light 100 do not invade a n<->-type impurity layer 11 of the photoelectric conversion element 5, contrary to the conventional case, and are pulled out toward the side of the n-type semiconductor substrate 1, so that smears can be decreased. In the horizontal electric charge transfer elements 6, electric charges are required to be transferred with a high speed and high transfer efficiency. Impurity concentration of the p-type well 3 should be adjusted to be an optimum value in order to perform low electric charge driving in the horizontal electric charge transfer elements 6. |
