Coating liquid for forming metal oxide film, metal oxide film, field-effect transistor, and method for producing field-effect transistor

• US 9,748,097 B2
• Filed: 03/26/2014
• Issued: 08/29/2017
• Est. Priority Date: 03/29/2013
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nakamura, Yuki, Ueda, Naoyuki, Matsumoto, Shinji, Takada, Mikiko, Sone, Yuji, Saotome, Ryoichi, Arae, Sadanori, Abe, Yukiko
• Primary Examiner(s): Gebreyesus, Yosef
• Application Number:
  US14/780,190
• Publication Number:
  US 20160042947A1
• Time in Patent Office: 1,252 Days
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing
• 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 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

To provide a coating liquid for forming a metal oxide film, containing: an indium compound; at least one selected from the group consisting of a magnesium compound, a calcium compound, a strontium compound, and a barium compound; at least one selected from the group consisting of a compound containing a metal a maximum positive value of an oxidation number of which is IV, a compound containing a metal a maximum positive value of an oxidation number of which is V, and a compound containing a metal a maximum positive value of an oxidation number of which is VI; and an organic solvent.

Claims

1. A coating liquid for farming a metal oxide film, comprising:

an indium compound;

at least one selected from the group consisting of a calcium compound and a barium compound;

at least one selected from the group consisting of a first compound containing a metal with a maximum positive value of an oxidation number of IV, a second compound containing a metal with a maximum positive value of an oxidation number of V, and a third compound containing a metal with a maximum positive value of an oxidation number of VI; and

an organic solvent.

2. The coating liquid according to claim 1,

wherein the third compound containing a metal with a maximum positive value of an oxidation number of VI is a molybdenum compound, or a tungsten compound, or both thereof.

3. The coating liquid according to claim 1,

wherein a number (A) of indium atoms of the indium compound, and a total number (C) of metal atoms of the first compound containing a metal with a maximum positive value of an oxidation number of IV, the second compound containing a metal with a maximum positive value of an oxidation number of V, and the third compound containing a metal with a maximum positive value of an oxidation number of VI satisfy the following formula (2):

0. 0001≦

[C/A]≦

0.1 

 

Formula (2).

4. The coating liquid according to claim 1,

wherein the indium compound is at least one selected from the group consisting of indium nitrate, indium sulfate, and indium chloride.

5. The coating liquid according to claim 1,

wherein the organic solvent is glycol ether, or diol, or both thereof.

6. The metal oxide film according to claim 1, obtained by a method comprising:

applying the coating liquid according to claim 1 onto a base to be coated; and

drying, followed by baking.

7. A field-effect transistor, comprising:

a gate electrode configured to apply gate voltage;

a source electrode and a drain electrode, which are configured to extract electric current;

an active layer, which is formed between the source electrode and the drain electrode, and is formed of oxide semiconductor; and

a gate insulating layer formed between the gate electrode, and the active layer,

wherein the oxide semiconductor is formed by applying the coating liquid according to claim 1.

8. A coating liquid for forming a metal oxide film comprising:

an indium compound;

at least one selected from the group consisting of a magnesium compound, a calcium compound, a strontium compound, and a barium compound;

at least one selected from the group consisting of a first compound containing a metal with a maximum positive value of an oxidation number of IV and a second compound containing a metal with a maximum positive value of an oxidation number of VI; and

an organic solvent,

wherein the first compound containing a metal with a maximum positive value of an oxidation number of IV is at least one selected from the group consisting of a zirconium compound and a hafnium compound.

9. A field-effect transistor, comprising:

a gate electrode configured to apply gate voltage;

a source electrode and a drain electrode, which are configured to extract electric current;

an active layer, which is formed between the source electrode and the drain electrode, and is formed of oxide semiconductor; and

a gate insulating layer formed between the gate electrode, and the active layer,

wherein the oxide semiconductor is formed by applying the coating liquid according to claim 8.

10. A coating liquid for forming a metal oxide film comprising:

an indium compound;

at least one selected from the group consisting of a magnesium compound, a calcium compound, a strontium compound, and a barium compound;

at least one selected from the group consisting of a first compound containing a metal with a maximum positive value of an oxidation number of V, and a second compound containing a metal with a maximum positive value of an oxidation number of VI; and

an organic solvent,

wherein the first compound containing a metal with a maximum positive value of an oxidation number of V is at least one selected from the group consisting of a vanadium compound, a niobium compound, and an antimony compound.

11. The coating liquid according to claim 10,

wherein a number (A) of indium atoms of the indium compound, and a total number (B) of magnesium atoms of the magnesium compound, calcium atoms of the calcium compound, strontium atoms of the strontium compound, and barium atoms of the barium compound satisfy the following formula (1):

0. 04≦

[B/A]≦

0.5 

 

Formula (1).

12. The coating liquid according to claim 10,

wherein the magnesium compound is at least one selected from the group consisting of magnesium nitrate, magnesium sulfate, and magnesium chloride, the calcium compound is at least one selected from the group consisting of calcium nitrate, calcium sulfate, and calcium chloride, the strontium compound is at least one selected from the group consisting of strontium nitrate, strontium sulfate, and strontium chloride, and the barium compound is barium bistetrahydrofurfuryloxide.

13. A method for forming a field-effect transistor, comprising:

forming a gate electrode on a base;

forming a gate insulating layer on the gate electrode;

forming a source electrode and a drain electrode on the gate insulating layer with a space between the source electrode and the drain electrode;

forming an active layer formed of oxide semiconductor on an area of the gate insulating layer, which is a channel region between the source electrode and the drain electrode,

wherein the forming the active layer is applying the coating liquid according to claim 10 on the gate insulating layer to form the active layer formed of the oxide semiconductor.

14. The method for producing a field-effect transistor according to claim 13,

wherein the forming the active layer comprises adjusting a number (A) of indium atoms of the indium compound, a total number (B) of magnesium atoms of the magnesium compound, calcium atoms of the calcium compound, strontium atoms of the strontium compound, and barium atoms of the barium compound, and a total number (C) of the metal atoms of the first compound containing a metal with a maximum positive value of an oxidation number of IV, the first compound containing a metal with a maximum positive value of an oxidation number of V, and the second compound containing a metal with a maximum positive value of an oxidation number of VI in the coating liquid for forming the metal oxide film, to thereby control at least one selected from the group consisting of volume resistivity, carrier mobility, and carrier density of the oxide semiconductor.

15. A method for producing a field-effect transistor, comprising:

forming a source electrode and a drain electrode on a base with a space between the source electrode and the drain electrode;

forming an active layer formed of oxide semiconductor on an area of the base, which is a channel region between the source electrode and the drain electrode;

forming a gate insulating layer on the active layer; and

forming a gate electrode on the gate insulating layer,

wherein the forming the active layer includes applying the coating liquid according to claim 10 on the base to form the active layer formed of the oxide semiconductor.

16. The method for producing a field-effect transistor according to claim 15,

wherein the forming the active layer comprises adjusting a number (A) of indium atoms of the indium compound, a total number (B) of magnesium atoms of the magnesium compound, calcium atoms of the calcium compound, strontium atoms of the strontium compound, and barium atoms of the barium compound, and a total number (C) of the metal atoms of the first compound containing a metal with a maximum positive value of an oxidation number of IV, the first compound containing a metal with a maximum positive value of an oxidation number of V, and the second compound containing a metal with a maximum positive value of an oxidation number of VI in the coating liquid for forming the metal oxide film, to thereby control at least one selected from the group consisting of volume resistivity, carrier mobility, and carrier density of the oxide semiconductor.

17. A field-effect transistor, comprising:

a gate electrode configured to apply gate voltage;

a source electrode and a drain electrode, which are configured to extract electric current;

an active layer, which is formed between the source electrode and the drain electrode, and is formed of oxide semiconductor; and

a gate insulating layer formed between the gate electrode, and the active layer,

wherein the oxide semiconductor is formed by applying the coating liquid according to claim 10.