Image sensor and method of fabricating the same

Patent metadata

Field	Value
Publication number	US-2018294310-A1
Application number	US-201715796994-A
Country	US
Kind code	A1
Filing date	Oct 30, 2017
Priority date	Apr 10, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

An image sensor may include: a trench formed in a substrate; an impurity region formed in the substrate to be in contact with the trench; and a re-crystallization layer formed in the substrate to be in contact with bottom and side surfaces of the trench and a surface of the substrate. The re-crystallization layer may contain one or more kinds of elements different from an element constituting the substrate.

First claim

What is claimed is:

1 . An image sensor comprising:
a trench formed in a substrate; an impurity region formed in the substrate to be in contact with the trench; and a re-crystallization layer formed in the substrate to be in contact with bottom and side surfaces of the trench and a surface of the substrate, wherein the re-crystallization layer contains one or more kinds of elements different from an element constituting the substrate.

2 . The image sensor of claim 1 , further comprising:
a photoelectric conversion element formed in the substrate, wherein the photoelectric conversion element comprises the purity region.

3 . The image sensor of claim 1 , wherein the trench has rounded corners.

4 . The image sensor of claim 1 , wherein the re-crystallization layer is continuously formed along the surface of the substrate, which includes the bottom and side surfaces of the trench.

5 . The image sensor of claim 1 , wherein the substrate comprises a light receiving region and a readout region, both of which are isolated from each other by the trench, and the element contained in the re-crystallization layer disposed in the light receiving region is different from the element contained in the re-crystallization layer disposed in the readout region.

6 . The image sensor of claim 1 , wherein the element constituting the substrate comprises silicon, and the one or more kinds of elements different from the element constituting the substrate comprise one or more of metalloid elements, nonmetallic elements, and combinations thereof among group 14 to 18 elements.

7 . An image sensor comprising:
a substrate having a first surface and a second surface facing the first surface; a trench formed at the first surface of the substrate; an impurity region formed in the substrate to be in contact with the trench; a first re-crystallization layer formed in the substrate to be in contact with bottom and side surfaces of the trench and the first surface of the substrate; and a second re-crystallization layer formed in the substrate to be in contact with the second surface of the substrate, wherein each of the first and second re-crystallization layers contains one or more kinds of elements different from an element constituting the substrate.

8 . The image sensor of claim 7 , further comprising:
a photoelectric conversion element formed in the substrate, wherein the photoelectric conversion element comprises the impurity region.

9 . The image sensor of claim 7 , wherein the trench has rounded corners.

10 . The image sensor of claim 7 , wherein the first re-crystallization layer is continuously formed along the first surface of the substrate, which includes the bottom and side surfaces of the trench, and the second re-crystallization layer is continuously formed along the second surface of the substrate.

11 . The image sensor of claim 7 , wherein the substrate comprises a light receiving region and a readout region, both of which are isolated from each other by the trench, and the element contained in the first re-crystallization layer disposed in the light receiving region is different from the element contained in the first re-crystallization layer disposed in the readout region.

12 . The image sensor of claim 7 , wherein the element constituting the substrate comprises silicon, and the one or more kinds of elements different from the element constituting the substrate comprise one or more of metalloid elements, nonmetallic elements, and combinations thereof among group 14 to 18 elements.

13 . A method of fabricating an image sensor, comprising:
forming a trench at a first surface of a substrate by etching the substrate having the first surface and a second surface facing the first surface; performing a primary ion-implantation process to form a first amorphous layer in the substrate such that the first amorphous layer is in contact with bottom and side surfaces of the trench and the first surface of the substrate; performing a primary anneal process to convert the first amorphous layer into a first re-crystallization layer; and forming an impurity region in the substrate such that the impurity region is in contact with the trench, wherein the primary ion-implantation process is performed using one or more kinds of elements different from an element constituting the substrate.

14 . The method of claim 13 , further comprising:
forming a photoelectric conversion element in the substrate, wherein the photoelectric conversion element comprises the purity region.

15 . The method of claim 13 , wherein after performing the primary ion-implantation process and performing the primary anneal process, the trench has rounded corners.

16 . The method of claim 13 , wherein the substrate comprises a light receiving region and a readout region, both of which are isolated from each other by the trench, and the element contained in the first re-crystallization layer disposed in the light receiving region is different from the element contained in the first re-crystallization layer disposed in the readout region.

17 . The method of claim 13 , wherein the first re-crystallization layer is formed in the substrate to be in contact with the bottom and side surfaces of the trench and the first surface of the substrate, and continuously formed along the first surface of the substrate, which includes the side and bottom surfaces of the trench.

18 . The method of claim 13 , wherein the element constituting the substrate comprises silicon, and the one or more kinds of elements different from the element constituting the substrate comprise one or more of metalloid elements, nonmetallic elements, and combinations thereof among group 14 to 18 elements.

19 . The method of claim 13 , further comprising:
performing a thinning process on the second surface of he substrate; performing a secondary ion-implantation process to form a second amorphous layer in the substrate such that the second amorphous layer is in contact with the second surface of the substrate; and performing a secondary anneal process to convert the second amorphous layer into a second re-crystallization layer, wherein the secondary ion-implantation process is performed using one or more kinds of elements different from the element constituting the substrate.

20 . The method of claim 19 , wherein the secondary anneal process is performed for a shorter time than the primary anneal process.

Assignees

• Sk Hynix Inc

Inventors

• Kim Byoung-Gyu

Classifications

• H04N25/63

  applied to dark current · CPC title

• H01L27/1461

  Electricity · mapped topic

• H01L27/14645

  Electricity · mapped topic

• H01L27/14698 Primary

  Electricity · mapped topic

• H04N5/361

  Electricity · mapped topic