Method of manufacturing PIN photodiode

A method of manufacturing a photodiode comprising the following steps:

• on a first silicon layer of the first electroconductive type, a second silicon layer of the second electroconductive type is formed;
• a silicon region of the second electroconductive type and having an impurity concentration higher than that of the second silicon layer is formed at a prescribed depth from the surface of the second silicon layer;
• a silicon oxide film is formed on the surface at least including said silicon region;
• and an antireflection film is formed to cover a portion or the entirety of said silicon oxide film;
• wherein:
• the resistivity of said silicon region is 0.02-2 Ω·cm,
• the resistivity of the second silicon layer is 2-4 Ω·cm,
• the depth of said silicon region from the surface of the second silicon layer is about 0.5 Å, and
• the thickness of said second silicon layer is about double said depth.

A method of manufacturing a semiconductor device having a photodiode and MOS transistor comprising the following steps:

• forming on a first silicon layer a p-type, a second silicon layer of an n-type;
• forming a silicon region of the n-type and having an impurity concentration higher than that of the second silicon layer at a prescribed depth from the surface of the second silicon layer;
• forming a gate oxide film of said MOS transistor is formed on the surface of said silicon region;
• forming an antireflection film to cover a portion or the entirety of said silicon oxide film of the photodiode;
• and forming an opening in an insulating film formed on the antireflection film to expose at least a portion of the antireflection film,
• wherein said gate oxide film is formed by thermal oxidation;
• wherein said antireflection film is a silicon nitride film;
• wherein the film thickness of said silicon oxide film is about 50-120 Å, and the film thickness of the silicon nitride film is about 400-600 Å, and
• wherein said gate oxide film decreases, on an interface between said gate oxide film and a surface of said second silicon layer, a number of dangling bonds of silicon,
• the resistivity of said silicon region is 0.02-2 Ω·cm, wherein
• the resistivity of the second silicon layer is 2-4 Ω·cm,
• the depth of said silicon region from the surface of the second silicon layer is about 0.5 Å, and
• the thickness of said second silicon layer is about double said depth.

A method of manufacturing a semiconductor device having a photodiode and MOS transistor comprising the following steps:

• on a first silicon layer of the first electroconductive type, a second silicon layer of the second electroconductive type is formed;
• a silicon region of the second electroconductive type and having an impurity concentration higher than that of the second silicon layer is formed;
• at a prescribed depth from the surface of the second silicon layer;
• when the gate oxide film of said MOS transistor is formed, said gate oxide film is formed on the surface of said silicon region;
• an antireflection film is formed to cover a portion or the entirety of said silicon oxide film of the photodiode;
• and an opening is formed in an insulating film formed on the antireflection film to expose at least a portion of the antireflection film
• further comprising a processing step in which when the polysilicon gate film of said MOS transistor is formed, said polysilicon gate film is formed on said gate oxide film, and said antireflection film is formed after the removal of said polysilicon gate film,
• wherein the resistivity of said silicon region is 0.02-2 Ω·cm, and its depth from the surface of the second silicon layer is about 0.5 μm.