Matsushita Electric Industrial Co., Ltd.

Shibata Jun

Kenichi Matsuda

Toyoji Chino

A device such as a phototransistor, a photodiode, a laser diode or the like including a compound semiconductor coated with a stable passivation film to reduce leakage current is disclosed. The passivation film includes oxygen, a metallic element and constituent elements of the device, and the concentration of the elements included in the passivation film changes gradually through the interface between the passivation film and the device. Such a passivation film is formed by the oxidation or anodic oxidation of a device soaked in an aqueous solution of hydrogen oxide containing metallic ions such as Fe.sup.2+, Fe.sup.3+, Cu.sup.+, Cu.sup.2+, Co.sup.2+ or Cr.sup.2+ under the control of the temperature of the solution.

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Kawachinagano, Japan

Shibata Jun