To improve light absorption efficiency and to increase an internal gain in an MIS type photodiode by thickening a film of a semiconductor layer in order to improve the sensitivity of a radiation detector.

After forming the film of the semiconductor layer, patterning is performed by using a photolithography method in order to mitigate the stress of the film, and the film of the semiconductor layer is formed again. By repeating a process two or more times, even when the film of the semiconductor layer is thickened, a situation that the film is peeled or an insulating substrate is warped by the film stress is avoided.