Solid-state imaging device including a photoelectric converting film and camera system using the solid-state imaging device
View Patent ↗A solid-state imaging device in the present disclosure includes a semiconductor substrate, pixels, and column signal lines. Each of the pixels includes an amplifying transistor, a selection transistor, a reset transistor, and a photoelectric converting unit. The photoelectric converting unit includes a photoelectric converting film, a transparent electrode, a pixel electrode, and an accumulation diode. The pixel electrode and the accumulation diode are connected to a gate of the amplifying transistor. The amplifying transistor has a source connected to the column signal line and a drain connected to a power source line. The reset transistor has a source connected to the pixel electrode. The selective transistor is provided between the source of the amplifying transistor and the column signal line. A threshold voltage of the amplifying transistor is lower than a voltage of the accumulation diode.
1. A solid-state imaging device comprising:
a semiconductor substrate;
pixels arranged on the semiconductor substrate in a matrix; and
vertical signal lines each formed for a corresponding one of columns of the pixels, wherein:
each of the pixels includes an amplifying transistor, a selection transistor, a reset transistor, and a photoelectric converting unit,
the photoelectric converting unit includes a photoelectric converting film formed above the semiconductor substrate, a transparent electrode formed above the photoelectric converting film, a pixel electrode formed below the photoelectric converting film, and an accumulation diode which accumulates signal charges to be obtained by the photoelectric converting film and is connected to the pixel electrode,
the pixel electrode and the accumulation diode are connected to a gate of the amplifying transistor,
the amplifying transistor has a source connected to the vertical signal line and a drain connected to a power source line,
the reset transistor has a source connected to the pixel electrode,
the selection transistor is provided one of (i) between the source of the amplifying transistor and the vertical signal line and (ii) between the drain of the amplifying transistor and the power source line,
a threshold voltage of the amplifying transistor is lower than a voltage of the accumulation diode, and
the power source line supplies (i) a predetermined voltage during a period when the selection transistor is on, and (ii) a voltage lower than the predetermined voltage during a period when the selection transistor is off.
2. The solid-state imaging device according to claim 1 ,
wherein, during a period when the reset transistor and the selection transistor are on, the voltage lower than the predetermined voltage is lower than a voltage provided from the amplifying transistor to the vertical signal line.
3. The solid-state imaging device according to claim 1 , further comprising
a load transistor provided between the vertical signal line and a fixed potential,
wherein during a period when the selection transistor is off, the load transistor is off and a voltage of the vertical signal line is lower than a voltage of the drain of the amplifying transistor.
4. The solid-state imaging device according to claim 3 ,
wherein the fixed potential is a negative potential.
5. The solid-state imaging device according to claim 1 ,
wherein the reset transistor has a drain connected to the vertical signal line via an inverting amplifier.
6. A camera system comprising the solid-state imaging device according to claim 1 .
7. A solid-state imaging device comprising:
a semiconductor substrate;
pixels arranged on the semiconductor substrate in a matrix; and
vertical signal lines each formed for a corresponding one of columns of the pixels, wherein: each of the pixels includes an amplifying transistor, a selection transistor, a reset transistor, and a photoelectric converting unit, the photoelectric converting unit includes a photoelectric converting film formed above the semiconductor substrate, a transparent electrode formed above the photoelectric converting film, a pixel electrode formed below the photoelectric converting film, and an accumulation diode which accumulates signal charges to be obtained by the photoelectric converting film and is connected to the pixel electrode,
the pixel electrode and the accumulation diode are connected to a gate of the amplifying transistor,
the amplifying transistor has a source connected to the vertical signal line and a drain connected to a power source line,
the reset transistor has a source connected to the pixel electrode,
the selection transistor is provided one of (i) between the source of the amplifying transistor and the vertical signal line and (ii) between the drain of the amplifying transistor and the power source line,
a threshold voltage of the amplifying transistor is lower than a voltage of the accumulation diode,
the accumulation diode comprises a n-type diffusion layer,
the photoelectric converting film converts incident light into electron-hole pairs as the signal charges, and
the holes of the electron-hole pairs are transferred to and accumulated in the n-type diffusion layer.
8. The solid-state imaging device according to claim 7 ,
wherein the power source line supplies (i) a predetermined voltage during a period when the selection transistor is on, and (ii) a voltage lower than the predetermined voltage during a period when the selection transistor is off.
9. The solid-state imaging device according to claim 8 ,
wherein, during a period when the reset transistor and the selection transistor are on, the voltage lower than the predetermined voltage is lower than a voltage provided from the amplifying transistor to the vertical signal line.
10. The solid-state imaging device according to claim 7 ,
wherein the reset transistor has a drain connected to the vertical signal line via an inverting amplifier.
11. A camera system comprising the solid-state imaging device according to claim 7 .