Sanyo Electric Co., Ltd.

Osamu Shiroma

Keiji Mita

A photodiode built-in semiconductor device is provided that can prevent internal peripheral circuits from erroneously operating due to incident light entering slantingly, or not perpendicular to a top surface of the semiconductor chip. A semiconductor chip 20 includes a photodiode and its peripheral circuits. The region except for the photodiode is covered with a light shielding film 22 of aluminum metallization. An isolation region (P.sup.+) 23 is arranged at an outermost portion of the chip. A dummy island 24 is formed so as to surround the entire portion of the chip 20. An N.sup.+ -type low resistance region 25 is formed in the surface of the dummy island 24. The dummy photodiode is formed by applying a reverse bias potential across the PN junction defined between the isolation region 23 and the dummy island 24.

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Ota, Japan

Osamu Shiroma