Infrared sensor, infrared sensor array, and method of manufacturing infrared sensor

An infrared sensor comprising:

• a base substrate;
• an infrared receiver;
• a first beam;
• and
• a second beam, wherein:
• each of the first beam and the second beam has a connection portion connected to the base substrate and/or a member on the base substrate and a separated portion away from the base substrate, and is physically joined to the infrared receiver at the separated portion,
• the infrared receiver is supported by the first beam and the second beam to be away from the base substrate,
• the infrared receiver includes a resistance change portion including a resistance change material an electrical resistance of which changes with temperature,
• the resistance change portion includes an amorphous semiconductor,
• each of the first beam and the second beam includes a crystalline semiconductor made of a base material same as a base material of the resistance change material, and is electrically connected to the resistance change portion at the separated portion,
• the first beam and the second beam are doped with impurities,
• a concentration of the impurities, with which the first beam and the second beam are doped, changes continuously at an interface between each of the first and second beams and the resistance change portion along a direction normal to the interface,
• in a vicinity of the interface, a gradient of the concentration of the impurities, with which the first beam and the second beam are doped, along the direction normal to the interface is smaller than or equal to 1018 cm−3/nm, and
• the vicinity of the interface is an area from the interface to a region a specified distance away from the interface in the direction normal to the interface.