| 摘要 |
PURPOSE:To apply a DC voltage between two electrodes and detect a light by providing the two electrodes on both surfaces of an impurity doped SiO2 film. CONSTITUTION:After a p-type Si substrate 20 is selectively oxidized and field oxide films 23 are formed, an element region is covered with a heat oxide film of 200Angstrom thickness and As ions are implanted. Then the oxide film on the surface of the element region is removed and again an oxide film 22 of 150-200Angstrom thickness is formed by heat oxidization. A doped polycrystalline Si layer 24 of 2000-3000Angstrom thickness is deposited on the oxide film 22 and patterned. The surface part of the polycrystalline Si layer 24 is converted into a blocking oxide film 25 of 300Angstrom thickness by heat oxidization and the whole surface of the substrate is covered with a PSG layer 26 of 1 mum thickness by CVD. As a light can he transmitted through the PSG film and is scarcely absorbed by the blocking oxide film, the detection of the light is hot obstructed and the light from the upper part can be detected without interference.
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