Solid-state imaging device, driving method for solid-state imaging device, and electronic appliance

A driving method for a solid-state imaging device including a pixel region having pixels arranged in two-dimensional array, each pixel comprising:

• a photoelectric conversion unit configured to generate signal charges corresponding to light quantity;
• a floating diffusion unit that is provided for a substrate and configured to convert the signal charges into voltage;
• a first charge accumulation unit that is provided for the substrate and configured to accumulate the signal charges generated in the photoelectric conversion unit;
• a second charge accumulation unit that is provided on the first charge accumulation unit in a substrate thickness direction and that is formed electrically isolated from the first charge accumulation unit;
• a first transfer transistor that includes a first transfer gate electrode formed embedded in the substrate to a depth of such a degree that the first transfer gate electrode reaches the first charge accumulation unit from a substrate surface provided with the second charge accumulation unit;
• a second transfer transistor configured to transfer the signal charges accumulated in the second charge accumulation unit to the floating diffusion unit, wherein:
• the signal charges accumulated in the first charge accumulation units and the photoelectric conversion units are transferred to the second charge accumulation units simultaneously in the entire pixels by turning on the first transfer transistors;
• and
• the signal charges held in the second charge accumulation units are read out for each row by turning on the second transfer transistors;
• and
• a reset transistor configured to reset the photoelectric conversion unit and the first charge accumulation unit, wherein the reset transistor includes a vertical reset transistor including a reset gate electrode formed embedded in the substrate to a depth of such a degree that the reset gate electrode reaches the first charge accumulation unit from the substrate surface.

An electronic appliance comprising:

• an optical lens;
• a solid-state imaging device to which light condensed by the optical lens is incident and which includes:
• a substrate,
• a photoelectric conversion unit configured to generate signal charges corresponding to light quantity,
• a floating diffusion unit that is provided for the substrate and configured to convert the signal charges into voltage,
• a first charge accumulation unit that is provided for the substrate and configured to accumulate the signal charges generated in the photoelectric conversion unit,
• a second charge accumulation unit that is provided on the first charge accumulation unit in a substrate thickness direction and that is formed electrically isolated from the first charge accumulation unit,
• a first transfer transistor that includes a first transfer gate electrode formed embedded in the substrate to a depth of such a degree that the first transfer gate electrode reaches the first charge accumulation unit from a substrate surface provided with the second charge accumulation unit,
• a second transfer transistor configured to transfer the signal charges accumulated in the second charge accumulation unit to the floating diffusion unit, and
• a reset transistor configured to reset the photoelectric conversion unit and the first charge accumulation unit, wherein the reset transistor includes a vertical reset transistor including a reset gate electrode formed embedded in the substrate to a depth of such a degree that the reset gate electrode reaches the first charge accumulation unit from the substrate surface;
• and
• a signal processing circuit configured to process an output signal output from the solid-state imaging device.