(JP10270744-A)      The photodiode includes a semiconductor substrate (11) over which a semiconductor layer (4) is formed. The substrate is of first conductivity type and the layer is of second conductivity type. Several isolation diffusion areas (2,5) are formed by dividing the semiconductor layer.    Due to the division, several adjacent semiconductor areas are formed. Several implanting diffusion areas (3) are respectively formed, adjacent to each semiconductor area.    USE -   CD-ROM, DVD.    ADVANTAGE -   Improves response speed of photodiode. Improves cut off frequency of photodiode. Suppresses detour of optical carrier.    (US6005278-A)      The divided photodiode includes an N-type semiconductor layer (4) formed on a P-type semiconductor substrate (11). Several isolating P-type diffusion regions (2,5) are each constituted by at least one layer. The isolating regions are formed in several regions in the semiconductor layer so as to respectively extend from a surface of the semiconductor layer opposite to the other surface in contact with a surface of the semiconductor substrate and to reach regions under the surface of the semiconductor substrate. The isolating regions divide the semiconductor layer into at least three N-type semiconductor regions.    Light is irradiated onto the vicinity of an isolating section in a combination of several semiconductor regions which are next to each other via the isolating section while light is irradiated onto a centre of the semiconductor region other than the combination of semiconductor regions. A first buried P-type diffusion region is further formed under the other isolating diffusion regions except for a particular one located in the isolating section in the combination of semiconductor regions, and a depletion of the semiconductor substrate in a region under the other isolating diffusion region by the application of a reverse bias to it is suppressed.    USE -   For pick-up used in CD-ROM, DVD etc.    ADVANTAGE -   Increases response speed.    (TW423103-A)      The divided photodiode includes an N-type semiconductor layer (4) formed on a P-type semiconductor substrate (11). Several isolating P-type diffusion regions (2,5) are each constituted by at least one layer. The isolating regions are formed in several regions in the semiconductor layer so as to respectively extend from a surface of the semiconductor layer opposite to the other surface in contact with a surface of the semiconductor substrate and to reach regions under the surface of the semiconductor substrate. The isolating regions divide the semiconductor layer into at least three N-type semiconductor regions.    Light is irradiated onto the vicinity of an isolating section in a combination of several semiconductor regions which are next to each other via the isolating section while light is irradiated onto a centre of the semiconductor region other than the combination of semiconductor regions. A first buried P-type diffusion region is further formed under the other isolating diffusion regions except for a particular one located in the isolating section in the combination of semiconductor regions, and a depletion of the semiconductor substrate in a region under the other isolating diffusion region by the application of a reverse bias to it is suppressed.    USE -   For pick-up used in CD-ROM, DVD etc.    ADVANTAGE -   Increases response speed.