PURPOSE: To improve blue color sensitivity by a method wherein ions are implanted in such a manner that the ratio dox/Rp of the thickness dox of an oxide film to the projected range Rp is controlled to be 0.9∼1.5 in manufacture of an MOS-type image sensor.

CONSTITUTION: A field oxide film 6, a gate oxide film 7 and a polycrystalline silicon layer 8 for a gate electrode are formed on a P-type substrate 1 and ion implantation is carried out to form a source region 10 and a drain region 11 with self-alignment. At that time, the ratio dox/Rp of the thickness of the oxide film 7 to the projected range Rp of the ions are controlled to be 0.9∼1.5. After that, a PSG film 12 is formed and subjected to a heat treatment and further wiring of a drain electrode 13 and so forth are performed. With this constitution, as the low concentration and the shallow diffusion depth of the diffused layer of the source region 10 can be obtained, blue color sensitivity can be improved even if ions are implanted into the gate layer 8 with high concentration.