Sensor and image pickup device

• US 8,084,743 B2
• Filed: 06/30/2008
• Issued: 12/27/2011
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.), Japan Science & Technology Trading Co. Limited, Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.), Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Inventors: Saito, Keishi, Hosono, Hideo, Kamiya, Toshio, Nomura, Kenji
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Bryant, Casey
• Application Number:
  US12/164,917
• Publication Number:
  US 20080290286A1
• Time in Patent Office: 1,275 Days
• Field of Search: 250/361.R, 250/370.09, 250/370.11, 257/43, 257/448, 257/E29.094, 257292-293, 257/444
• US Class Current: 250/370.08
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14658 X-ray, gamma-ray or corpuscular radiation imagers measuring X-, gamma- or corpuscular radiation G01T1/00
• 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 31/02322 comprising luminescent members, e.g. fluorescent sheets upon the device
• CPC Class Codes: H01L 31/032 including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
• CPC Class Codes: H01L 31/085 the device being sensitive to very short wavelength, e.g. X-ray, Gamma-rays
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• CPC Class Codes: H01L 31/118 of the surface barrier or shallow PN junction detector type, e.g. surface barrier alpha-particle detectors

Abstract

A sensor for detecting a received electromagnetic wave comprising a first electrode, a second electrode and an amorphous oxide layer interposed between the first electrode and the second electrode.

Claims

1. An image pickup device comprising:

a flexible substrate;

an X-ray sensor arranged on the flexible substrate; and

a field effect transistor for reading a signal from the X-ray sensor, wherein;

an active layer of the field effect transistor comprises an amorphous oxide of a compound having

(a) a composition when in a crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds and

(b) an electron carrier concentration of 10¹²/cm³ or more and less than 10¹⁸/cm³, wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.

2. An image pickup device according to claim 1, further comprising a non-flat imaging region.

3. An image pickup device according to claim 1, wherein the X-ray sensor includes a scintillator for converting X-ray into light and an opto-electric conversion element.

11. An active matrix display according to any one of claims 1, 4, 5, 9 or 10, wherein the transistor satisfies the condition of V_DS×

I_DS/(W/L)≦

1.5×

10<sup>−

5</sup>(V×

A) at V_GS=0V, wherein V_DS is drain-source voltage, I_DS is drain-source current, V_GS is gate voltage, W is width of channel and L is length of channel.

12. An active matrix display according to any one of claims 1, 4, 5, 9 or 10, wherein the transistor satisfies the condition of V_DS×

I_DS/(W/L)≦

7.5×

10<sup>−

8</sup>(V×

A) at V_GS=0V, wherein V_DS is drain-source voltage, I_DS is drain-source current, V_GS is gate voltage, W is width of channel and L is length of channel.

4. An image pickup device comprising:

a substrate having a non-flat region;

an X-ray sensor provided on the substrate; and

a field effect transistor for reading a signal from the X-ray sensor,

wherein the field effect transistor is a normally-off transistor having an active layer composed of an amorphous oxide of a compound having

(a) a composition when in a crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds and

(b) an electron carrier concentration of 10¹²/cm³ or more and less than 10¹⁸/cm³, wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.

5. An image pickup device comprising:

a sensor for detecting an electromagnetic wave; and

a field effect transistor for reading a signal from the sensor,

wherein the field effect transistor has as an active layer an amorphous oxide semiconductor layer composed of an amorphous oxide of a compound having

(a) a composition when in a crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds and

(b) an electron carrier concentration of 10¹²/cm³ or more and less than 10¹⁸/cm³, wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.

6. An image pickup device according to claim 5, wherein the amorphous oxide semiconductor layer additionally contains at least one of Sn and a Group IV element selected from Si, Ge or Zr.

7. An image pickup device according to claim 5, wherein the amorphous oxide semiconductor layer contains In, Ga, and Zn.

8. An image pickup device according to claim 5, wherein the sensor is an X-ray sensor, and the X-ray sensor includes a scintillator for converting X-ray into light, and the sensor detects the light as the electromagnetic wave.

9. An image pickup device comprising:

a substrate;

an X-ray sensor arranged on the substrate; and

a field effect transistor for reading a signal from the X-ray sensor, wherein;

an active layer of the field effect transistor comprises an amorphous oxide of a compound having

(a) a composition when in a crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds and

(b) an electron carrier concentration of 10¹²/cm³ or more and less than 10¹⁸/cm³, wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.

10. An image pickup device comprising:

a substrate;

an X-ray sensor provided on the substrate; and

a field effect transistor for reading a signal from the X-ray sensor,

wherein the field effect transistor is a normally-off transistor having an active layer composed of an amorphous oxide of a compound having

(a) a composition when in a crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds and

(b) an electron carrier concentration of 10¹²/cm³ or more and less than 10¹⁸/cm³, wherein an electron mobility of the active layer tends to increase with increasing electron carrier concentration and wherein a current between drain and source terminals of the field effect transistor when no gate voltage is applied is less than 10 microamperes.