Abstract: One object of the present invention is to provide a method or apparatus for purifying target particles from high-concentration particles in a short time. The above problem can be solved by a method for purifying target particles, characterized in that the method comprises a step of sorting the target particles from a high concentration of non-target particles, wherein the sorting step is repeated for three times or more.

Abstract: This invention provides a semiconductor device including a silicon layer, an insulating layer formed on the silicon layer, a first semiconductor device formed on the insulating film to convert light into an electric signal, and a second semiconductor device formed on the insulating film, wherein a silicon region is formed in the silicon layer to shield the second semiconductor device from light, and a through hole extending through the silicon layer except for the silicon region to input light to the first semiconductor device is formed in that portion of the silicon layer corresponding to the lower portions of the first and second semiconductor devices.