SPAD image sensor and associated fabricating method
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorYuichiro Yamashita
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Abstract
A single photon avalanche diode (SPAD) image sensor is disclosed. The SPAD image sensor includes: a substrate having a front surface and a back surface; wherein the substrate includes a sensing region, and the sensing region includes: a common node heavily doped with dopants of a first conductivity type, the common node being within the substrate and abutting the back surface of the substrate; a sensing node heavily doped with dopants of a second conductivity type opposite to the first conductivity type, the sensing node being within the substrate and abutting the front surface of the substrate; and a first layer doped with dopants of the first conductivity type between the common node and the sensing node.
Claims20
A method of fabricating a single photon avalanche diode (SPAD) image sensor, the method comprising:
- receiving a substrate having a front surface and a back surface, wherein the substrate has a first layer doped with dopants of a first conductivity type extending from the front surface to the back surface of the substrate;
- forming two isolations extending from the front surface of the substrate toward the back surface of the substrate;
- performing an ion implantation upon the substrate with dopants of a second conductivity type opposite to the first conductivity type to form a second layer along the front surface of the substrate to immediately abut the front surface of the substrate and immediately abut at least one of the isolations;
- performing an ion implantation upon the front surface of the substrate with dopants of the second conductivity type opposite to the first conductivity type to form a sensing node within the second layer;
- and
- performing an ion implantation upon the back surface of the substrate with dopants of the first conductivity type to form a common node.
A method of fabricating a single photon avalanche diode (SPAD) image sensor, the method comprising:
- receiving a substrate having a front surface and a back surface, wherein the substrate has a first layer doped with dopants of a first conductivity type extending from the front surface to the back surface of the substrate;
- forming at least two trench isolations extending from the front surface of the substrate toward the back surface of the substrate;
- performing an ion implantation upon the front surface of the substrate with dopants of a second conductivity type opposite to the first conductivity type to form a second layer to fully fills gaps between the at least two trench isolations;
- and
- performing an ion implantation upon the front surface of the substrate with dopants of the second conductivity type to form a sensing node within the second layer.
A method of fabricating a single photon avalanche diode (SPAD) image sensor, the method comprising:
- receiving a substrate having a front surface and a back surface, wherein the substrate has a first layer doped with dopants of a first conductivity type extending from the front surface to the back surface of the substrate;
- forming trench isolations extending from the front surface of the substrate toward the back surface of the substrate;
- performing an ion implantation upon the front surface of the substrate with dopants of a second conductivity type opposite to the first conductivity type to form a second layer to fully fills gaps between the trench isolations;
- performing an ion implantation upon the front surface of the substrate with dopants of the second conductivity type to form a sensing node within the second layer;
- and
- performing an ion implantation upon the front surface of the substrate with dopants of the first conductivity type to form a third layer in the first layer and immediately abuts the second layer.
Dependencies are inferred from the claim text.