Phototransistor of CMOS image sensor and method for fabricating the same
First Claim
1. A method for fabricating a phototransistor of a CMOS image sensor comprising:
- defining an active area and a device isolation area in a first conductive type semiconductor substrate by forming an STI layer in the first conductive type semiconductor substrate;
forming a second conductive type well in the first conductive type semiconductor substrate, wherein the first conductive type is different from the second conductive type;
forming a gate oxide layer on art entire surface of the first conductive type semiconductor substrate;
forming a contact hole for exposing the predetermined portion of the second conductive type well below the STI layer by selectively removing the gate oxide layer and the STI layer;
forming an ohmic contact layer by implanting second conductive type impurity ions into the second conductive type well below the contact hole using the gate oxide layer as a mask;
forming a contact by filling the contact hole with a conductive material; and
forming a gate line over the first conductive type semiconductor substrate including the contact.
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Abstract
A phototransistor of a CMOS image sensor suitable for decreasing the size of layout, and a method for fabricating the phototransistor are disclosed, in which the phototransistor includes a first conductive type semiconductor substrate; an STI layer on the first conductive type semiconductor substrate, to define an active area and a device isolation area in the first conductive type semiconductor substrate; a second conductive type well in the first conductive type semiconductor substrate; a gate line on the first conductive type semiconductor substrate; an ohmic contact layer in the second conductive type well, wherein the ohmic contact layer is overlapped with the gate line in state of interposing the STI layer therebetween; and a contact to connect the gate line with the ohmic contact layer through the STI layer.
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Citations
16 Claims
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1. A method for fabricating a phototransistor of a CMOS image sensor comprising:
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defining an active area and a device isolation area in a first conductive type semiconductor substrate by forming an STI layer in the first conductive type semiconductor substrate; forming a second conductive type well in the first conductive type semiconductor substrate, wherein the first conductive type is different from the second conductive type; forming a gate oxide layer on art entire surface of the first conductive type semiconductor substrate; forming a contact hole for exposing the predetermined portion of the second conductive type well below the STI layer by selectively removing the gate oxide layer and the STI layer; forming an ohmic contact layer by implanting second conductive type impurity ions into the second conductive type well below the contact hole using the gate oxide layer as a mask; forming a contact by filling the contact hole with a conductive material; and forming a gate line over the first conductive type semiconductor substrate including the contact. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification