Analog circuit and semiconductor device

• US 8,242,837 B2
• Filed: 10/19/2010
• Issued: 08/14/2012
• Est. Priority Date: 10/21/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koyama, Jun, Hirose, Atsushi, Tsubuku, Masashi, Noda, Kosei
• Primary Examiner(s): Zweizig, Jeffrey
• Application Number:
  US12/907,559
• Publication Number:
  US 20110090006A1
• Time in Patent Office: 665 Days
• Field of Search: 327/512, 327/514, 327/538, 327/543, 327/564, 327/565, 327/566, 327/567, 327/574, 327/581
• US Class Current: 327/581
• CPC Class Codes: H01L 21/823412 with a particular manufacturing method of the channel structures, e.g. channel implants, halo or pocket implants, or channel materials
• 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 27/156 two-dimensional arrays
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• 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 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/00 Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof H10K50/00 takes precedence; devices consisting of a plurality of semiconductor components formed in or on a common substrate and including semiconductor components having potential barriers, specially adapted for light emission H01L27/15; semiconductor lasers H01S5/00
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H04M 1/0266 for a display module assembly
• CPC Class Codes: H04R 1/02 Casings; Cabinets ; Supports therefor; Mountings therein H04R1/28 takes precedence ; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]

Abstract

An object is to obtain a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range, using a thin film transistor in which an oxide semiconductor layer is used. An analog circuit is formed with the use of a thin film transistor including an oxide semiconductor which has a function as a channel formation layer, has a hydrogen concentration of 5×10¹⁹ atoms/cm³ or lower, and substantially functions as an insulator in the state where no electric field is generated. Thus, a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range can be obtained.

Claims

1. An analog circuit comprising:

a reference transistor;

a mirror transistor; and

a detector,

wherein the reference transistor is electrically connected to the detector,

wherein a drain and a gate of the reference transistor are electrically connected to each other,

wherein the gate of the reference transistor is electrically connected to a gate of the mirror transistor, and

wherein the reference transistor and the mirror transistor include an oxide semiconductor having a hydrogen concentration of 5×

10¹⁹ atoms/cm³ or lower.

2. The analog circuit according to claim 1, wherein the mirror transistor includes a plurality of thin film transistors connected in parallel to each other.

3. The analog circuit according to claim 1, wherein the mirror transistor has a longer channel width than the reference transistor.

4. The analog circuit according to claim 1, wherein a channel region of the oxide semiconductor has a carrier concentration of 5×

10¹⁴/cm³ or lower.

5. The analog circuit according to claim 1, wherein the detector is selected from the group consisting of a photosensor, an audio sensor and a temperature sensor.

6. A semiconductor device comprising the analog circuit according to claim 1.

7. An analog circuit comprising:

a first thin film transistor having a first terminal which is electrically connected to a high potential side power supply;

a second thin film transistor having a first terminal which is electrically connected to the high potential side power supply; and

a detector between the high potential side power supply and the first terminal of the first thin film transistor,

wherein a gate of the first thin film transistor is electrically connected to a point between the detector and the first terminal of the first thin film transistor,

wherein a gate of the second thin film transistor is electrically connected to the gate of the first thin film transistor,

wherein a second terminal of the first thin film transistor and a second terminal of the second thin film transistor are electrically connected to a low potential side power supply, and

wherein the first thin film transistor and the second thin film transistor include an oxide semiconductor having a hydrogen concentration of 5×

10¹⁹ atoms/cm³ or lower.

8. The analog circuit according to claim 7, wherein the second thin film transistor includes a plurality of thin film transistors connected in parallel to each other.

9. The analog circuit according to claim 7, wherein the second thin film transistor has a longer channel width than the first thin film transistor.

10. The analog circuit according to claim 7, wherein a channel region of the oxide semiconductor has a carrier concentration of 5×

10¹⁴/cm³ or lower.

11. The analog circuit according to claim 7, wherein the detector is selected from the group consisting of a photosensor, an audio sensor and a temperature sensor.

12. A semiconductor device comprising the analog circuit according to claim 7.