LOGIC CIRCUIT AND SEMICONDUCTOR DEVICE

• US 20110090184A1
• Filed: 10/12/2010
• Published: 04/21/2011
• Est. Priority Date: 10/16/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, KOYAMA, Jun, NODA, Kosei, TSUBUKU, Masashi
• Granted Patent: US 8,952,726 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2300/0439 Pixel structures
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G11C 19/184 with field-effect transistors, e.g. MOS-FET
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H03K 17/161 : in field-effect transistor switches
• CPC Class Codes: H03K 19/00315 : in field-effect transistor circuits
• CPC Class Codes: H03K 19/096 : Synchronous circuits, i.e. using clock signals H03K19/01728, H03K19/01855 take precedence

Abstract

To reduce a leakage current of a transistor so that malfunction of a logic circuit can be suppressed. The logic circuit includes a transistor which includes an oxide semiconductor layer having a function of a channel formation layer and in which an off current is 1×10⁻¹³ A or less per micrometer in channel width. A first signal, a second signal, and a third signal that is a clock signal are input as input signals. A fourth signal and a fifth signal whose voltage states are set in accordance with the first to third signals which have been input are output as output signals.

Claims

1. A logic circuit comprising:

a transistor comprising an oxide semiconductor layer including a channel formation layer,

wherein an off current is 1×

10<sup>−

13</sup> A or less per micrometer in channel width in the transistor,

wherein a first signal, a second signal, and a third signal that is a clock signal are input as input signals, and

wherein a fourth signal and a fifth signal whose voltage states are set in accordance with the first signal, the second signal, and the third signal which are input are output as output signals.

2. The logic circuit according to claim 1,

wherein an off current is 1×

10<sup>−

17</sup> A or less per micrometer in channel width in the transistor.

3. The logic circuit according to claim 1,

wherein a carrier concentration of the oxide semiconductor layer is 1×

10¹⁴/cm³ or less in the transistor.

4. The logic circuit according to claim 1, further comprising:

a first unit logic circuit which outputs the fourth signal whose voltage state is set in accordance with the first to third signals which are input, and

a second unit logic circuit which outputs the fifth signal whose voltage state is set in accordance with the first to third signals which are input.

5. A semiconductor device comprising:

a driver circuit provided with a shift register including the logic circuit according to claim 1; and

a pixel portion including a pixel whose display state is controlled by the driver circuit.

6. A logic circuit comprising:

a first unit logic circuit to which a first signal, a second signal, and a third signal that is a clock signal are input as input signals and which outputs a fourth signal whose voltage state is set in accordance with the first to third signals which are input, and

a second unit logic circuit to which the first signal, the second signal, and the third signal that is a clock signal are input as input signals and which outputs a fifth signal whose voltage state is set in accordance with the first to third signals which are input,

wherein the first unit logic circuit and the second unit logic circuit each include;

a first transistor comprising a gate, a source, and a drain, where the third signal is input to the gate and one of the first signal and the second signal is input to one of the source and the drain,

a second transistor comprising a gate, a source, and a drain, where the gate is electrically connected to the other of the source and the drain of the first transistor, one of a high power supply voltage and a low power supply voltage is applied to one of the source and the drain, and a voltage of the other of the source and the drain is a voltage of the fourth signal or the fifth signal,

a first capacitor comprising a first electrode and a second electrode, where the first electrode is electrically connected to the gate of the second transistor and the second electrode is electrically connected to the other of the source and the drain of the second transistor,

a third transistor comprising a gate, a source, and a drain, where the third signal is input to the gate and the other of the first signal and the second signal is input to one of the source and the drain,

a fourth transistor comprising a gate, a source, and a drain, where the gate is electrically connected to the other of the source and the drain of the third transistor, one of the source and the drain is electrically connected to one of the source and the drain of the second transistor, the other of the high power supply voltage and the low power supply voltage is input to the other of the source and the drain, and

a second capacitor comprising a first electrode and a second electrode, where the first electrode is electrically connected to the other of the source and the drain of the third transistor, and the other of the high power supply voltage and the low power supply voltage is input to the second electrode, and

wherein the first to fourth transistors each comprise an oxide semiconductor layer including a channel formation layer, where an off current is 1×

10<sup>−

13</sup> A or less per micrometer in channel width.

7. The logic circuit according to claim 6,

wherein an off current is 1×

10<sup>−

17</sup> A or less per micrometer in channel width in the first to fourth transistors.

8. The logic circuit according to claim 6,

wherein a carrier concentration of the oxide semiconductor layer is 1×

10¹⁴/cm³ or less in each of the first to fourth transistors.

9. A semiconductor device comprising:

a driver circuit provided with a shift register including the logic circuit according to claim 6; and

a pixel portion including a pixel whose display state is controlled by the driver circuit.

10. A logic circuit comprising:

a first unit logic circuit to which a first signal, a second signal, and a third signal that is a clock signal are input as input signals and which outputs a fourth signal whose voltage state is set in accordance with the first to third signals which are input, and

a second unit logic circuit to which the first signal, the second signal, and the third signal that is a clock signal are input as input signals and which outputs a fifth signal whose voltage state is set in accordance with the first to third signals which are input,

wherein the first unit logic circuit and the second unit logic circuit each include;

a first transistor comprising a gate, a source, and a drain, where the third signal is input to the gate and one of the first signal and the second signal is input to one of the source and the drain,

a second transistor comprising a gate, a source, and a drain, where the gate is electrically connected to the other of the source and the drain of the first transistor, one of a high power supply voltage and a low power supply voltage is applied to one of the source and the drain, and a voltage of the other of the source and the drain is a voltage of the fourth signal or the fifth signal,

a first capacitor comprising a first electrode and a second electrode, where the first electrode is electrically connected to the gate of the second transistor and the second electrode is electrically connected to the other of the source and the drain of the second transistor,

a third transistor comprising a gate, a source, and a drain, where the third signal is input to the gate and the other of the first signal and the second signal is input to one of the source and the drain,

a fourth transistor comprising a gate, a source, and a drain, where the gate is electrically connected to the other of the source and the drain of the third transistor, one of the source and the drain is electrically connected to one of the source and the drain of the second transistor, the other of the high power supply voltage and the low power supply voltage is input to the other of the source and the drain, and

a second capacitor comprising a first electrode and a second electrode, where the first electrode is electrically connected to the other of the source and the drain of the third transistor, and the other of the high power supply voltage and the low power supply voltage is input to the second electrode, and

wherein the first to fourth transistors each comprise an oxide semiconductor layer whose carrier concentration is 1×

10¹⁴/cm³ or less.

11. A semiconductor device comprising:

a driver circuit provided with a shift register including the logic circuit according to claim 10; and

a pixel portion including a pixel whose display state is controlled by the driver circuit.