Image sensor and manufacturing method thereof
An image sensor includes a photosensitive device, a storage device, and a driving circuit. The storage device is adjacent to the photosensitive device and includes a storage node, a gate dielectric layer, a storage gate electrode, and etch stop layer, a shielding layer, and a protection layer. The gate dielectric layer is over the storage node. The storage gate electrode is over the gate dielectric layer. The etch stop layer covers the gate dielectric layer and the storage gate electrode. The shielding layer is over the storage gate electrode. The protection layer is sandwiched between the etch stop layer and the shielding layer. The driving circuit is adjacent to the storage device.
1. An image sensor, comprising:
a photosensitive device;
a storage device adjacent to the photosensitive device, comprising:
a storage node;
a gate dielectric layer over the storage node;
a storage gate electrode over the gate dielectric layer;
an etch stop layer covering the gate dielectric layer and the storage gate electrode;
a shielding layer over the storage gate electrode; and
a protection layer sandwiched between the etch stop layer and the shielding layer; and
a driving circuit adjacent to the storage device.
2. The image sensor according to claim 1 , wherein the storage device further comprises a dielectric layer over the shielding layer.
3. The image sensor according to claim 2 , further comprising:
an interconnection structure disposed over the dielectric layer; and
a conductive contact penetrating through the dielectric layer and the etch stop layer to electrically connect the interconnection structure and the storage gate electrode.
4. The image sensor according to claim 1 , wherein the storage node comprises a P-N junction.
5. The image sensor according to claim 1 , wherein the shielding layer is electrically grounded.
6. The image sensor according to claim 1 , wherein a thickness of the protection layer ranges between 100 Å and 300 Å.
7. The image sensor according to claim 1 , wherein a material of the protection layer comprises SiO 2 or SiN.
8. An image sensor, comprising:
a storage device, comprising:
a substrate;
a P-N junction, located within the substrate;
a gate dielectric layer over the substrate;
a storage gate electrode over the gate dielectric layer;
a shielding layer over the storage gate electrode;
a protection layer covering a bottom surface and sidewalls of the shielding layer; and
a dielectric layer over the shielding layer;
a photosensitive device adjacent to the storage device, wherein the photosensitive device is located within the substrate; and
a driving circuit adjacent to the storage device.
9. The image sensor according to claim 8 , wherein the storage device further comprises an etch stop layer, wherein the etch stop layer is sandwiched between the protection layer and the storage gate electrode, the etch stop layer is sandwiched between the protection layer and the gate dielectric layer, the etch stop layer is sandwiched between the dielectric layer and the gate dielectric layer, and the etch stop layer is sandwiched between the dielectric layer and the storage gate electrode.
10. The image sensor according to claim 9 , further comprising:
an interconnection structure disposed over the dielectric layer; and
a conductive contact penetrating through the dielectric layer and the etch stop layer to electrically connect the interconnection structure and the storage gate electrode.
11. The image sensor according to claim 10 , wherein the shielding layer surrounds the conductive contact.
12. The image sensor according to claim 8 , wherein the shielding layer is electrically grounded through the substrate.
13. The image sensor according to claim 8 , wherein a thickness of the protection layer ranges between 100 Å and 300 Å.
14. The image sensor according to claim 8 , wherein a material of the protection layer comprises SiO 2 or SiN.