Patent ID: 6841807

Claim:
A PIN photodiode comprising: a first conductive-type semiconductor substrate; an intrinsic semiconductor layer and a second conductive-type semiconductor layer formed on the first conductive-type semiconductor substrate in sequence; a first insulation layer formed on the second conductive-type semiconductor layer, in which a window is formed in the center part of the first insulation layer so that the intrinsic semiconductor layer is exposed; a second-conductive type active layer formed on the intrinsic semiconductor layer within the window; a first electrode formed on the first insulation layer in contact with the second conductive-type active layer; and, a gate electrode structure consisting of a second insulation layer and a second electrode formed on the second conductive-type semiconductor layer and for applying an electric voltage of a second polarity, so that the lateral extension of the active layer is controlled at the time when an electric voltage of a first polarity is applied to the first electrode formed on the first insulation layer.