infrared ray sensor and method for fabricating the same , the method including the steps of forming a diaphragm on a substrate , forming and patterning a semiconductor film on the diaphragm to form a first thermoelectric material film , and forming and patterning a conductor film on the diaphragm , to form a metal resistance layer in a region of the first thermoelectric material film and a second thermoelectric material film in a region of the diaphragm , forming a protection film on an entire surface inclusive of the metal resistance layer , forming a black body on the protection film , and removing a back side portion of the substrate , to expose the diaphragm , whereby maintaining a high sensitivity , requiring no additional process , reducing jhonson noise , and improving yield .