MOS type solid-state imager and manufacturing method thereof
AssigneeKabushiki Kaisha Toshiba
InventorHiroaki Ishiwata
Life of this patent
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Abstract
A photodiode and a read gate are formed within an element region. A p+ type punch-through preventing region is not formed immediately under an n-type signal accumulating region of a photodiode. The n-type signal accumulating region is formed within a p-type semiconductor substrate. The p+ type punch-through preventing region is formed over the entire element region. The p+ type punch-through preventing region is also formed immediately under an insulative isolation layer in order to prevent punch-through between elements. A p+ type punch-through stopper is formed immediately under an n-type first semiconductor region.
Claims21
A MOS type solid-state imager comprising:
- a photoelectric conversion element formed in a semiconductor substrate of a first conductive type;
- a first MOS transistor of a second conductive type formed in a first element region of the semiconductor substrate, for reading out a charge generated by the photoelectric conversion element;
- a second MOS transistor of the second conductive type formed in a second element region of the semiconductor substrate;
- and
- a punch-though preventing region of the first conductive type formed over the second element region, for preventing punch-through.
A method of manufacturing a MOS type solid-state imager comprising the steps of:
- forming an insulative isolation layer on a semiconductor substrate of a first conductive type, thereby forming first and second element regions surrounded by the insulative isolation layer;
- doping an impurity of the first conductive type in the semiconductor substrate by an ion implantation method, thereby forming a punch-through preventing region of the first conductive type at least immediately under the insulative isolation layer and over the second element region, to prevent punch-through;
- forming a photoelectric conversion element and a first MOS transistor in the first element region, for reading out charge generated by the photoelectric conversion element and the photoelectric conversion element, and simultaneously forming a second MOS transistor in the second element region.
Dependencies are inferred from the claim text.