MODULATION CIRCUIT AND SEMICONDUCTOR DEVICE INCLUDING THE SAME

• US 20110121911A1
• Filed: 11/17/2010
• Published: 05/26/2011
• Est. Priority Date: 11/20/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KAMATA, Koichiro
• Granted Patent: US 9,350,295 B2
• Time in Patent Office: Days
• US Class Current: 332/149
• CPC Class Codes: G06K 19/07775 the antenna being on-chip
• CPC Class Codes: H01L 2223/6677 for antenna, e.g. antenna included within housing of semiconductor device antennas per se H01Q
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 28/20 Resistors
• CPC Class Codes: H01L 28/40 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: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H03C 1/36 by means of semiconductor device having at least three electrodes H03C1/34, H03C1/50, H03C1/52, H03C1/62 take precedence
• CPC Class Codes: H04M 2201/04 Transistors
• CPC Class Codes: H04M 2201/06 Integrated circuits

Abstract

A modulation circuit includes a load and a transistor serving as a switch. The transistor has an oxide semiconductor layer in which hydrogen concentration is 5×10¹⁹/cm³ or less. The off-state current of the transistor is 1×10⁻¹³ A or less. A modulation circuit includes a load, a transistor serving as a switch, and a diode. The load, the transistor, and the diode are connected in series between the terminals of an antenna. The transistor has an oxide semiconductor layer in which hydrogen concentration is 5×10¹⁹/cm³ or less. An off-state current of the transistor is 1×10⁻¹³ A or less. On/off of the transistor is controlled in accordance with a signal inputted to a gate of the transistor. The load is a resistor, a capacitor, or a combination of a resistor and a capacitor.

Claims

1. A modulation circuit comprising:

a load; and

a transistor comprising an oxide semiconductor layer,

wherein hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹/cm³, and

wherein an off-state current of the transistor is less than or equal to 1×

10<sup>−

13</sup> A.

2. The modulation circuit according to claim 1, wherein whether the transistor is on-state or off-state is controlled in accordance with a signal inputted to a gate of the transistor.

3. The modulation circuit according to claim 1, wherein the load comprises at least one of a resistor and a capacitor.

4. A cellular phone comprising the modulation circuit according to claim 1.

5. A semiconductor device comprising:

an antenna; and

a modulation circuit comprising;

a load; and

a transistor comprising an oxide semiconductor layer,

wherein one of a source and a drain of the transistor is electrically connected to one terminal of the antenna through the load, and the other of the source and the drain of the transistor is electrically connected to the other terminal of the antenna,

wherein hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹/cm³, and

wherein an off-state current of the transistor is less than or equal to 1×

10<sup>−

13</sup> A.

6. The semiconductor device according to claim 5, wherein whether the transistor is on-state or off-state is controlled in accordance with a signal inputted to a gate of the transistor.

7. The semiconductor device according to claim 5, wherein the load comprises at least one of a resistor and a capacitor.

8. A semiconductor device according to claim 5;

further comprising a rectifier circuit, a demodulation circuit, a constant voltage circuit and a logic circuit.

9. A cellular phone comprising the semiconductor device according to claim 5.

10. A semiconductor device comprising:

an antenna; and

a modulation circuit comprising;

a load;

a transistor comprising an oxide semiconductor layer; and

a diode,

wherein one of a source and a drain of the transistor is electrically connected to one terminal of the antenna through the load and the diode and the other of the source and the drain of the transistor is electrically connected to the other terminal of the antenna,

wherein hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹/cm³, and

wherein an off-state current of the transistor is less than or equal to 1×

10<sup>−

13</sup> A.

11. The modulation circuit according to claim 10, wherein the diode is a diode-connected transistor.

12. The modulation circuit according to claim 10, wherein whether the transistor is on-state or off-state is controlled in accordance with a signal inputted to a gate of the transistor.

13. The modulation circuit according to claim 10, wherein the load comprises at least one of a resistor and a capacitor.

14. A semiconductor device according to claim 10;

further comprising a rectifier circuit, a demodulation circuit, a constant voltage circuit and a logic circuit.

15. A cellular phone comprising the semiconductor device according to claim 10.