Image sensor having an active pattern of metal oxide semiconductor doped with nitrogen disposed on a hydrogen blocking layer
An image sensor includes a substrate including a plurality of pixels and having a first surface and a second surface opposite to the first surface, a photoelectric conversion portion disposed in the substrate in each of the pixels, a transfer gate disposed on the first surface of the substrate in each of the pixels, a first interlayer insulating layer covering the substrate and the transfer gate, a first hydrogen blocking layer disposed on the first interlayer insulating layer, a first active pattern disposed on the first hydrogen blocking layer and including a metal oxide doped with nitrogen, a first gate disposed on the first active pattern, a second interlayer insulating layer covering the first gate and the first active pattern, and upper source/drain contacts penetrating the second interlayer insulating layer and contacting the first active pattern at two sides of the first gate.
1 . An image sensor, comprising:
a substrate comprising a plurality of pixels and having a first surface and a second surface opposite to the first surface;
a photoelectric conversion portion disposed in the substrate in each of the pixels;
a transfer gate disposed on the first surface of the substrate in each of the pixels;
a first interlayer insulating layer covering the substrate and the transfer gate;
a first hydrogen blocking layer including only a single layer, disposed on the first interlayer insulating layer, and comprising SiOC or Al 2 O 3 ;
a first active pattern directly contacting the SiOC or the Al 2 O 3 of the first hydrogen blocking layer and comprising a metal oxide doped with nitrogen;
a first gate disposed on the first active pattern;
a second interlayer insulating layer covering the first gate and the first active pattern; and
upper source/drain contacts penetrating the second interlayer insulating layer and contacting the first active pattern at two sides of the first gate,
wherein a hydrogen concentration of the first hydrogen blocking layer is less than a hydrogen concentration of the first interlayer insulating layer,
a difference between a content of the nitrogen at a top end of the first active pattern and a content of the nitrogen at a bottom end of the first active pattern is within a range from about 0.0 at % to about 0.1 at %, and
a content of the nitrogen in the first active pattern is within a range from about 0.1 at % to about 5.0 at %.
2 . The image sensor of claim 1 , further comprising:
a floating diffusion region disposed in the substrate at a side of the transfer gate in each of the pixels; and
an interconnection structure penetrating the first interlayer insulating layer, the first hydrogen blocking layer and the second interlayer insulating layer, and connecting the floating diffusion region to one of the upper source/drain contacts,
wherein the first gate is a reset gate.
3 . The image sensor of claim 1 , further comprising:
a source follower gate disposed on the first surface of the substrate in each of the pixels and spaced apart from the transfer gate;
a lower source/drain region disposed in the substrate at a side of the source follower gate; and
an interconnection structure penetrating the first interlayer insulating layer, the first hydrogen blocking layer and the second interlayer insulating layer, and connecting the lower source/drain region to one of the upper source/drain contacts,
wherein the first gate is a selection gate.
4 . The image sensor of claim 1 , further comprising:
upper source/drain regions in contact with bottom surfaces of the upper source/drain contacts and disposed in the first active pattern,
wherein the upper source/drain regions comprise at least one of hydrogen, fluorine, or argon.
5 . The image sensor of claim 1 , further comprising:
a gate insulating layer disposed between the first active pattern and the first gate, and covering an entire top surface of the first active pattern,
wherein the gate insulating layer comprises aluminum oxide.
6 . The image sensor of claim 1 , further comprising:
a second hydrogen blocking layer disposed on the second interlayer insulating layer.
7 . The image sensor of claim 1 , wherein a portion of the second interlayer insulating layer is a gate insulating layer disposed between the first gate and the first active pattern.
8 . The image sensor of claim 1 , wherein a top surface and a sidewall of the first gate are in contact with the second interlayer insulating layer.
9 . The image sensor of claim 8 , further comprising:
a gate capping pattern disposed on the transfer gate; and
a gate spacer covering a sidewall of the transfer gate.
10 . The image sensor of claim 1 , wherein the metal oxide comprises at least one metal of In, Ga, Zn, or Sn.
11 . An image sensor, comprising:
a substrate comprising a plurality of pixels and having a first surface and a second surface opposite to the first surface;
a pixel isolation portion disposed in the substrate, wherein the pixel isolation portion isolates the pixels from each other;
a photoelectric conversion portion disposed in the substrate in each of the pixels;
a transfer gate disposed on the first surface of the substrate in each of the pixels;
a floating diffusion region disposed in the substrate at a side of the transfer gate in each of the pixels;
a first interlayer insulating layer covering the substrate and the transfer gate;
a first hydrogen blocking layer including only a single layer, disposed on the first interlayer insulating layer, and comprising SiOC or Al 2 O 3 ;
a first active pattern directly contacting the SiOC or the Al 2 O 3 of the first hydrogen blocking layer, wherein the first active pattern comprises a metal oxide doped with nitrogen;
a first gate disposed on the first active pattern;
a second interlayer insulating layer covering the first gate and the first active pattern; and
upper source/drain contacts penetrating the second interlayer insulating layer and contacting the first active pattern at two sides of the first gate,
wherein a hydrogen concentration of the first hydrogen blocking layer is less than a hydrogen concentration of the first interlayer insulating layer,
a difference between a content of the nitrogen at a top end of the first active pattern and a content of the nitrogen at a bottom end of the first active pattern is within a range from about 0.0 at % to about 0.1 at %, and
a content of the nitrogen in the first active pattern is within a range from about 0.1 at % to about 5.0 at %.
12 . The image sensor of claim 11 , further comprising:
an interconnection structure penetrating the first interlayer insulating layer, the first hydrogen blocking layer and the second interlayer insulating layer, and connecting the floating diffusion region to one of the upper source/drain contacts,
wherein the first gate is a reset gate.
13 . The image sensor of claim 11 , further comprising:
a source follower gate disposed on the first surface of the substrate in each of the pixels and spaced apart from the transfer gate;
a lower source/drain region disposed in the substrate at a side of the source follower gate; and
an interconnection structure penetrating the first interlayer insulating layer, the first hydrogen blocking layer and the second interlayer insulating layer, and connecting the lower source/drain region to one of the upper source/drain contacts,
wherein the first gate is a selection gate.