Circuit substrate, detector, and method of manufacturing the same

A circuit substrate manufacturing method characterized by comprising the steps of:

• forming an electrical insulating region in a semiconductor substrate having a PN junction in a thickness direction, having a high concentration of an impurity of one conductivity type, and having conductivity, said electrical insulating region being made of a heat-resistant insulating material, continuously extending from an upper surface to a lower surface of said semiconductor substrate, and being closed in a plane parallel to the surface of said semiconductor substrate, and separating said semiconductor substrate into first and second electrically insulated/isolated regions, said first region being surrounded by said electrical insulating region and said second region being outside said electrical insulating region;
• and
• removing a region, of said first region, which has the other conductivity type.

A circuit substrate manufacturing method characterized by comprising the steps of:

• forming an electrical insulating region in one semiconductor layer having conductivity and made up of two semiconductor layers and an oxide layer formed between said semiconductor layers, said one semiconductor layer having a high impurity concentration to have conductivity, and said electrical insulating region being made of a heat-resistant insulating material, continuously extending from an upper surface of said one semiconductor layer to said oxide layer, and being closed in a plane parallel to the surface of said semiconductor substrate;
• and
• forming a contact hole in said oxide layer and the other semiconductor layer of said substrate in correspondence with a first region of said one semiconductor layer.