Image sensor and a method of manufacturing the same
An image sensor includes a substrate including a plurality of pixel regions, a first surface, and a second surface that is opposite to the first surface, and a deep device isolation pattern penetrating the substrate and between the plurality of pixel regions, the deep device isolation pattern including a first filling pattern adjacent to the second surface, a second filling pattern on the first filling pattern and adjacent to the first surface, a semiconductor pattern between the first filling pattern and the substrate, an oxidized semiconductor pattern on the semiconductor pattern and between the substrate and the second filling pattern, and a side insulating pattern between the semiconductor pattern and the substrate, where the semiconductor pattern directly contacts the oxidized semiconductor pattern.
1 . An image sensor comprising:
a substrate comprising:
a plurality of pixel regions;
a first surface; and
a second surface that is opposite to the first surface; and
a deep device isolation pattern penetrating the substrate and between the plurality of pixel regions, the deep device isolation pattern comprising:
a first filling pattern adjacent to the second surface;
a second filling pattern on the first filling pattern and adjacent to the first surface;
a semiconductor pattern between the first filling pattern and the substrate;
an oxidized semiconductor pattern on the semiconductor pattern and between the substrate and the second filling pattern; and
a side insulating pattern between the semiconductor pattern and the substrate,
wherein the semiconductor pattern directly contacts the oxidized semiconductor pattern.
2 . The image sensor of claim 1 , wherein the semiconductor pattern comprises a semiconductor material doped with at least one P-type dopant or at least one N-type dopant, and
wherein the oxidized semiconductor pattern comprises an oxide of the semiconductor material.
3 . The image sensor of claim 1 , wherein the second filling pattern comprises silicon oxide.
4 . The image sensor of claim 1 , wherein a thickness of a top surface of the first filling pattern in a direction parallel to the first surface of the substrate is less than a thickness of a bottom surface of the first filling pattern in the direction parallel to the first surface of the substrate.
5 . The image sensor of claim 1 , further comprising:
a shallow device isolation pattern adjacent to the first surface of the substrate,
wherein a bottom surface of the shallow device isolation pattern is at a level that is substantially the same as a level of a top surface of the first filling pattern.
6 . The image sensor of claim 1 , wherein inner side surfaces of the semiconductor pattern are spaced apart in a first direction parallel to the first surface of the substrate,
wherein the first filling pattern is between the inner side surfaces of the semiconductor pattern, and
wherein a distance between the inner side surfaces of the semiconductor pattern is substantially constant along an increasing height in a second direction perpendicular to the first surface of the substrate.
7 . The image sensor of claim 1 , wherein the side insulating pattern comprises:
a single layer comprising silicon oxide; or
a multi-layer comprising silicon oxide.
8 . The image sensor of claim 1 , wherein the first filling pattern comprises a material that is the same as a material of the second filling pattern.
9 . The image sensor of claim 1 , further comprising:
a back device isolation pattern extending from the second surface into the substrate,
wherein the back device isolation pattern comprises a horizontal width that is greater than a horizontal width of the deep device isolation pattern in a cross-sectional view.
10 . The image sensor of claim 1 , wherein the substrate further comprises:
a central region, wherein the plurality of pixel regions are in the central region; and
an edge region surrounding the central region in a plan view, and
wherein the image sensor further comprises a contact pattern extending in the substrate and contacting a bottom surface of the semiconductor pattern in the edge region.
11 . A method of manufacturing an image sensor, the method comprising:
preparing a substrate comprising a first surface and a second surface that is opposite to the first surface;
forming a deep trench extending from the first surface into the substrate;
forming a side insulating layer at least partially covering an inner surface of the deep trench;
forming a semiconductor layer at least partially covering the side insulating layer;
forming a first filling layer filling the deep trench on the semiconductor layer;
forming a second trench and a first filling pattern by performing etching on the first filling layer; and
forming an oxidized semiconductor layer by oxidizing a first portion of the semiconductor layer which is exposed by the second trench,
wherein a second portion of the semiconductor layer that is different from the first portion of the semiconductor layer is formed into a semiconductor pattern.
12 . The method of claim 11 , further comprising:
forming a device isolation layer adjacent to the first surface of the substrate,
wherein the forming of the first filling pattern comprises:
etching the first filling layer such that a top surface of the first filling pattern is located at a height that is substantially the same as a height of a bottom surface of the device isolation layer.
13 . The method of claim 11 , wherein the semiconductor layer comprises a substantially uniform thickness.
14 . The method of claim 11 , further comprising:
after the forming of the oxidized semiconductor layer, forming a second filling layer substantially filling the second trench,
wherein the second filling layer comprises silicon oxide.
15 . The method of claim 14 , further comprising, after the forming of the second filling layer:
performing a planarization process in which the oxidized semiconductor layer is etched; and
performing a thinning process in which an oxidized semiconductor pattern is formed.
16 . The method of claim 11 , wherein the forming of the semiconductor layer comprises:
depositing a preliminary semiconductor layer; and
doping the preliminary semiconductor layer with at least one P-type dopant or at least one N-type dopant.
17 . The method of claim 11 , wherein a depth of the second trench ranges from about 50% to about 90% of a depth of the deep trench.
18 . An image sensor comprising:
a substrate comprising:
a plurality of pixel regions;
a first surface; and
a second surface that is opposite to the first surface,
wherein the plurality of pixel regions are arranged in a first direction and a second direction that are intersecting and that are parallel to the second surface;
a deep device isolation pattern extending from the first surface into the substrate in a third direction perpendicular to the second surface and that is between the plurality of pixel regions; and
a shallow device isolation pattern adjacent to the first surface,
wherein the deep device isolation pattern comprises:
a first filling pattern adjacent to the second surface;
a second filling pattern on the first filling pattern and penetrating the shallow device isolation pattern;
a semiconductor pattern between the first filling pattern and the substrate;
an oxidized semiconductor pattern on the semiconductor pattern, and between the shallow device isolation pattern and the second filling pattern; and
a side insulating pattern between the semiconductor pattern and the substrate.
19 . The image sensor of claim 18 , wherein the semiconductor pattern comprises a semiconductor material doped with at least one P-type dopant or at least one N-type dopant, and
wherein the oxidized semiconductor pattern comprises an oxide of the semiconductor material.
20 . The image sensor of claim 19 , wherein the semiconductor pattern comprises silicon doped with boron, and
wherein the oxidized semiconductor pattern comprises silicon oxide doped with boron.