US 7,791,012 B2Granted

Semiconductor device comprising photoelectric conversion element and high-potential and low-potential electrodes

AssigneeSemiconductor Energy Laboratory Co., Ltd.

InventorAtsushi Hirose

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Abstract

To suppress a decrease in photosensitivity of a photoelectric conversion element provided in a semiconductor device by reducing the parasitic resistance of an amplifier circuit. In addition, the amplifier circuit which amplifies the output current of the photoelectric conversion element is operated stably. A semiconductor device includes a photoelectric conversion element, a current mirror circuit having at least two thin film transistors, a high-potential power supply electrically connected to each of the thin film transistors, and a low-potential power supply electrically connected to each of the thin film transistors. When a reference thin film transistor is an n-type, the reference thin film transistor is placed closer to the low-potential power supply than an output thin film transistor is. When a reference thin film transistor is a p-type, the reference thin film transistor is placed closer to the high-potential power supply than an output thin film transistor is.

Claims12

Dependent claims

A semiconductor device comprising:

a photoelectric conversion element having a square plane;
a current mirror circuit including a reference thin film transistor and a plurality of output thin film transistors, the current mirror circuit amplifying an output of the photoelectric conversion element;
a high-potential electrode arranged at a first side of the photoelectric conversion element;
and
a low-potential electrode arranged at a second side of the photoelectric conversion element;
wherein both the reference thin film transistor and the plurality of output thin film transistors are n-type thin film transistors,
wherein one of source and drain electrodes of the reference thin film transistor is electrically connected to the high-potential electrode through the photoelectric conversion element,
wherein one of source and drain electrodes of each of the plurality of output thin film transistors is electrically connected to the high-potential electrode,
wherein the other of the source and drain electrodes of the reference thin film transistor is electrically connected to the low-potential electrode,
wherein the other of the source and drain electrodes of each of the plurality of output thin film transistors is electrically connected to the low-potential electrode,
wherein the plurality of output thin film transistors are provided in an L-shape region extending from a vicinity of the high-potential electrode to a vicinity of the low-potential electrode along the first side and the second side, and
wherein the reference thin film transistor is provided in the vicinity of the low-potential electrode.

9 more elements

A semiconductor device comprising:

a photoelectric conversion element having a square plane;
a current mirror circuit including a reference thin film transistor and a plurality of output thin film transistors, the current mirror circuit amplifying an output of the photoelectric conversion element;
a high-potential electrode arranged at a first side of the photoelectric conversion element;
and
a low-potential electrode arranged at a second side of the photoelectric conversion element;
wherein both the reference thin film transistor and the plurality of output thin film transistors are n-type thin film transistors,
wherein one of source and drain electrodes of the reference thin film transistor is electrically connected to the high-potential electrode through the photoelectric conversion element,
wherein one of source and drain electrodes of each of the plurality of output thin film transistors is electrically connected to the high-potential electrode,
wherein the other of the source and drain electrodes of the reference thin film transistor is electrically connected to the low-potential electrode,
wherein the other of the source and drain electrodes of each of the plurality of output thin film transistors is electrically connected to the low-potential electrode,
wherein a current path between the reference thin film transistor and the low-potential electrode is shorter than a current path between each of the plurality of output thin film transistors and the low-potential electrode,
wherein the plurality of output thin film transistors are provided in an L-shape region extending from a vicinity of the high-potential electrode to a vicinity of the low-potential electrode along the first side and the second side, and
wherein the reference thin film transistor is provided in the vicinity of the low-potential electrode.

10 more elements

A semiconductor device comprising:

a photoelectric conversion element having a square plane;
a current mirror circuit including a reference thin film transistor and a plurality of output thin film transistors, the current mirror circuit amplifying an output of the photoelectric conversion element;
a high-potential electrode arranged at a first side of the photoelectric conversion element;
a low-potential electrode arranged at a second side of the photoelectric conversion element;
a battery electrically connected to the high-potential electrode and the low-potential electrode;
an antenna for receiving a signal;
a rectifier circuit for rectifying the signal received at the antenna;
and
a charging circuit for charging the battery based on an output of the rectifier circuit,
wherein both the reference thin film transistor and the plurality of output thin film transistors are n-type thin film transistors,
wherein one of source and drain electrodes of the reference thin film transistor is electrically connected to the high-potential electrode through the photoelectric conversion element,
wherein one of source and drain electrodes of each of the plurality of output thin film transistors are electrically connected to the high-potential electrode,
wherein the other of the source and drain electrodes of the reference thin film transistor is electrically connected to the low-potential electrode,
wherein the other of the source and drain electrodes of each of the plurality of output thin film transistors are electrically connected to the low-potential electrode,
wherein the plurality of output thin film transistors are provided in an L-shape region extending from a vicinity of the high-potential electrode to a vicinity of the low-potential electrode along the first side and the second side, and
wherein the reference thin film transistor is provided in the vicinity of the low-potential electrode.

13 more elements

A semiconductor device comprising:

a photoelectric conversion element having a square plane;
a current mirror circuit including a reference thin film transistor and a plurality of output thin film transistors, the current mirror circuit amplifying an output of the photoelectric conversion element;
a high-potential electrode arranged at a first side of the photoelectric conversion element;
a low-potential electrode arranged at a second side of the photoelectric conversion element;
a battery electrically connected to the high-potential electrode and the low-potential electrode;
an antenna for receiving a signal;
a rectifier circuit for rectifying the signal received at the antenna;
and
a charging circuit for charging the battery based on an output of the rectifier circuit,
wherein both the reference thin film transistor and the plurality of output thin film transistors are n-type thin film transistors,
wherein one of source and drain electrodes of the reference thin film transistor is electrically connected to the high-potential electrode through the photoelectric conversion element,
wherein one of source and drain electrodes of each of the plurality of output thin film transistors are electrically connected to the high-potential electrode,
wherein the other of the source and drain electrodes of the reference thin film transistor is electrically connected to the low-potential electrode,
wherein the other of the source and drain electrodes of each of the plurality of output thin film transistors are electrically connected to the low-potential electrode,
wherein a current path between the reference thin film transistor and the low-potential electrode is shorter than a current path between each of the plurality of output thin film transistors and the low-potential electrode,
wherein the plurality of output thin film transistors are provided in an L-shape region extending from a vicinity of the high-potential electrode to a vicinity of the low-potential electrode along the first side and the second side, and
wherein the reference thin film transistor is provided in the vicinity of the low-potential electrode.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/898,834Filed 17 Sep 2007
Priority: JP 2006-26885429 Sep 2006
Published: US 2008/0078923 A13 Apr 2008
Granted: 7 Sep 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H10F 39/026
Manufacture or treatment of image sensors covered by group H10F39/12: wafer-level processing
G01J 1/44
Using electric radiation detectors: electric circuits
H04N 23/65
Control of cameras or camera modules: control of camera operation in relation to power supply
H04N 23/71
Circuitry for compensating brightness variation in the scene: circuitry for evaluating the brightness variation