Abstract: An interline transfer type image sensing device that can be operated at high speed and with low image smear is described. The device incorporates a refractory metal layer which is used for both a light shield over the vertical charge transfer region and as a wiring layer for low resistance strapping of poly crystalline silicon (polysilicon) gate electrodes for the vertical charge transfer region. Plugs provided by a separate metallization layer connect the refractory light shield to the polysilicon gate electrode. These plugs allow high temperature processing after refractory light shield patterning for improved sensor performance without degradation of the polysilicon gate electrode or the refractory lightshield layer.

Abstract: A photodetector is integrated on a single semiconductor chip with bipolar transistors including a high speed poly-emitter vertical NPN transistor. The photodetector includes a silicon nitride layer serving as an anti-reflective film. The silicon nitride layer and oxide layers on opposite sides thereof insulate edges of a polysilicon emitter from the underlying transistor regions, minimizing the parasitic capacitance between the NPN transistor's emitter and achieving a high frequency response. The method of manufacture is compatible with existing BiCMOS process technology, the silicon nitride layer of the anti-reflective film being formed over the photodetector as well as regions of the chip that include the vertical NPN transistor and other circuit elements.