Photodiode, ultraviolet sensor having the photodiode, and method of producing the photodiode

A method of producing a photodiode, comprising the steps of:

• preparing a semiconductor wafer including a silicon semiconductor layer, a low concentration diffusion layer with one of a P-type impurity and an N-type impurity diffused therein at a low concentration, a P-type high concentration diffusion layer with the P-type impurity diffused therein at a first high concentration, and an N-type high concentration diffusion layer with the N-type impurity diffused therein at a second high concentration, said low concentration diffusion layer being formed in the silicon semiconductor layer so that the P-type high concentration diffusion layer and the N-type high concentration diffusion layer are arranged to face each other with the low concentration diffusion layer in between;
• forming an insulation material layer on the silicon semiconductor layer;
• performing a thermal process on the semiconductor wafer under hydrogen atmosphere to form an UV-A filter between the low concentration diffusion layer and the interlayer insulation film for blocking ultraviolet light, said UV-A filter including a covalent bond between silicon and hydrogen adjacent to the interlayer insulation film
• forming a first contact plug in the interlayer insulation film so that the first contact plug contacts with the N-type high concentration diffusion layer;
• and
• forming a first wiring portion on the interlayer insulation film so that the first wiring portion contacts with the first contact plug, said first wiring portion being arranged in a first area where the low concentration diffusion layer does not exist on an opposite side of the interlayer insulation film.