CMOS image sensor
View Patent ↗Embodiments relate to a vertical-type CMOS image sensor, a method of manufacturing the same, and a method of gettering the same, in which source and drain regions are expanded to improve grounding and gettering effects. In embodiments, the vertical-type CMOS image sensor may include a silicon substrate, a first photodiode formed in a prescribed part of the silicon substrate, a first epitaxial layer formed on the silicon substrate, a second photodiode formed on the first epitaxial layer to overlap the first photodiode, a second epitaxial layer formed on the first epitaxial layer, a third photodiode formed on the second epitaxial layer to overlap the second photodiode, and first to third grounded dummy moats formed by implanting impurities into uniform parts on the silicon substrate, the first epitaxial layer, and the second epitaxial layer.
1. A device, comprising:
a silicon substrate;
a first photodiode formed in a prescribed part of the silicon substrate;
a first epitaxial layer formed over the silicon substrate;
a second photodiode formed on the first epitaxial layer to overlap the first photodiode;
a second epitaxial layer formed on the first epitaxial layer;
a third photodiode formed on the second epitaxial layer to overlap the second photodiode; and
first, second, and third dummy moats formed by implanting impurities into uniform parts on the silicon substrate, the first epitaxial layer, and the second epitaxial layer, wherein:
the first dummy moat is floating below a surface of the silicon substrate;
the second dummy moat is floating below a surface of the first epitaxial layer; and
the third dummy moat is floating below a surface of the second epitaxial layer.
2. The device of claim 1 , wherein the first, second, and third dummy moats are grounded.
3. The device of claim 1 , wherein a first impurity ion is implanted into the first, second, and third photodiodes, and wherein a second impurity ion is implanted into the first, second, and third dummy moats.
4. The device of claim 3 , wherein the first impurity ion comprises an n+ type, and wherein the second impurity ion comprises a p+ type.
5. The device of claim 4 , wherein the second impurity ion comprises boron (B).
6. The device of claim 1 , wherein the first, second, and third dummy moats are electrically connected to external grounding terminals.
7. A device, comprising:
a silicon substrate including a photodiode;
a plurality of epitaxial layers formed over the silicon substrate, each epitaxial layer including a photodiode; and
a plurality of first dummy moats formed in respective ones of the plurality of epitaxial layers by implanting impurities, wherein each of the plurality of first dummy moats is floating below a surface of the plurality of epitaxial layers.
8. The device of claim 7 , further comprising a second dummy moat formed in the silicon substrate, wherein the second dummy moat is floating below a surface of the silicon substrate.
9. The device of claim 8 , where in each of the photodiodes is configured to overlap with a photodiode in an adjacent layer, and wherein each of the plurality of first dummy moats and the second dummy moat are formed away from the corresponding photodiode formed on respective layers.
10. The device of claim 9 , wherein a first impurity ion is used to form each of the photodiodes, and where in a second impurity ion is used to form each of the dummy moats.
11. The device of claim 10 , wherein each of the dummy moats is grounded.