Image sensor having an active pattern of metal oxide semiconductor doped with nitrogen disposed on a hydrogen blocking layer

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 Al2O3;
• a first active pattern directly contacting the SiOC or the Al2O3 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 %.