Solid-state imaging device with floating diffusion layer

1. A solid-state imaging apparatus, comprising:

a plurality of photosensitive cells disposed in a matrix in a photosensitive region on a semiconductor substrate; and

a driving unit for driving the plurality of photosensitive cells,

wherein each of the photosensitive cells includes:

a photodiode formed to be exposed on a surface of the semiconductor substrate, for accumulating signal charge obtained by subjecting incident light to photoelectric exchange;

a transfer transistor formed on the semiconductor substrate, for transferring the signal charge accumulated in the photodiode;

a floating diffusion layer formed on the semiconductor substrate, for temporarily accumulating the signal charge transferred by the transfer transistor, the floating diffusion layer including a contact portion that is connected to a gate electrode of an amplifier transistor; and

the amplifier transistor being formed on the semiconductor substrate, for amplifying the signal charge temporarily accumulated in the floating diffusion layer,

wherein a source/drain diffusion layer provided in the amplifier transistor is covered with a salicide layer,

the floating diffusion layer is formed to be exposed on the surface of the semiconductor substrate in a region other than a periphery of the contact portion of the floating diffusion layer, while a region within the periphery of the contact portion is covered with a second salicide layer, and

an impurity concentration of the floating diffusion layer is lower than an impurity concentration of the source/drain diffusion layer of the amplifier transistor.

2. The solid-state imaging apparatus according to claim 1 , wherein the transfer transistor and the amplifier transistor are composed of an n-type MOS transistor.

3. The solid-state imaging apparatus according to claim 1 , wherein the impurity concentration of the floating diffusion layer is 1×10 18 cm 31 3 or less.

4. A solid-state imaging apparatus, comprising:

a plurality of photosensitive cells disposed in a matrix in a photosensitive region on a semiconductor substrate; and

a driving unit for driving the plurality of photosensitive cells,

wherein each of the photosensitive cells includes:

a photodiode formed to be exposed on a surface of the semiconductor substrate, for accumulating signal charge obtained by subjecting incident light to photoelectric exchange;

a transfer transistor formed on the semiconductor substrate, for transferring the signal charge accumulated in the photodiode;

a floating diffusion layer formed on the semiconductor substrate, for temporarily accumulating the signal charge transferred by the transfer transistor, the floating diffusion layer including a contact portion that is connected to a gate electrode of an amplifier transistor; and

the amplifier transistor being formed on the semiconductor substrate, for amplifying the signal charge temporarily accumulated in the floating diffusion layer,

wherein a source/drain diffusion layer provided in the amplifier transistor is covered with a salicide layer,

the floating diffusion layer is formed to be exposed on the surface of the semiconductor substrate in a region other than a periphery of the contact portion of the floating diffusion layer, while a region within the periphery of the contact portion is covered with a second salicide layer,

each of the photosensitive cells further includes a reset transistor for resetting the floating diffusion layer,

the driving unit includes:

a vertical driver circuit for simultaneously driving the transfer transistor and the reset transistor in a vertical direction;

a noise suppressing circuit for obtaining a signal output to a plurality of vertical signal lines disposed in a vertical direction in the photosensitive region; and

a horizontal driver circuit for outputting a signal from the noise suppressing circuit in a time series by successively switching a plurality of horizontal transistors disposed in a horizontal direction, and

an impurity concentration of the floating diffusion layer is lower than an impurity concentration of a source/drain diffusion layer provided in a plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit.

5. The solid-state imaging apparatus according to claim 4 , wherein the source/drain diffusion layer provided in the plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit is covered with a salicide layer.

6. The solid-state imaging apparatus according to claim 4 , wherein the vertical driver circuit and the horizontal driver circuit are composed of a dynamic logic circuit.

7. The solid-state imaging apparatus according to claim 4 , wherein an impurity concentration of a source/drain diffusion layer of a part of the plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit is lower than an impurity concentration of a source/drain diffusion layer of another part of the plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit.

8. The solid-state imaging apparatus according to claim 4 , wherein a source/drain diffusion layer of a part of the plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit is formed to be exposed on the surface of the semiconductor substrate, and a source/drain diffusion layer of another part of the plurality of transistors constituting the vertical driver circuit and the horizontal driver circuit is covered with a salicide layer.