Solution deposition of metal salts to form metal oxides

Patent metadata

Field	Value
Publication number	US-2023416105-A1
Application number	US-202318464678-A
Country	US
Kind code	A1
Filing date	Sep 11, 2023
Priority date	Jun 17, 2019
Publication date	Dec 28, 2023
Grant date	—

Abstract

Certain disclosed embodiments concern an organic solution suitable for forming metal oxide films, particularly thins films, comprising a metal salt selected from a Sn salt, an Sb salt, a dopant, and combinations thereof. The salt often is a halide salt, such as SnCl 2 or SbCl 3 . Certain disclosed compositions are preferably formed using substantially pure reagents and may include a dopant, such as a fluoride dopant. Described solutions may be used to form thin films, such as a thin film comprising SnO 2 , Sb:SnO 2 , F:SnO 2 , or (Sb,F):SnO 2 . Such thin films may have any desired thickness, such as a thickness of from 200 or 700 nm, and are extremely smooth, such as having an RMS surface roughness >3 nm, such as 3 nm to 10 nm, with certain embodiments having an RMS surface roughness <2 nm or <1 nm. Devices can be assembled comprising the thin films on a suitable substrate.

First claim

We claim:

1 . A method for making a metal oxide thin film, comprising:
preparing an organic solution comprising a solvent; a metal salt selected from a Sn salt, an Sb salt, and combinations thereof; and a dopant; spin-coating or die-slot coating the solution onto a substrate to form a film on the substrate, where the film has a thickness of greater than 200 nm to 700 nm and an RMS surface roughness of 2 nm or less measured over an area of at least 1×1 μm 2 ; and heating the film.

2 . The method according to claim 1 where the metal salt is a halide salt.

3 . The method according to claim 2 where the metal salt is SnCl 2 or SbCl 3 .

4 . The method according to claim 1 wherein the metal salt, or salts, has a purity of greater than 99.9%.

5 . The method according to claim 1 where the dopant is a fluoride dopant selected from HF, NH 4 F, (CH 3 ) 4 NF, CF 3 COOH, SnF 2 , SnF 4 , or a combination thereof.

6 . The method according to claim 1 wherein the solvent is a nitrile, an ether, or a combination thereof.

7 . The method according to claim 6 where the solvent is acetonitrile, tetrahydrofuran, or a combination thereof.

8 . The method according to claim 1 , wherein the organic solution comprises:
an organic solvent selected from a nitrile, an ether, or a combination thereof; a metal halide salt selected from SnCl 2 , SbCl 3 , or combinations thereof; and a fluoride dopant selected from HF, NH 4 F, (CH 3 ) 4 NF, CF 3 COOH, SnF 2 , SnF 4 , or a combination thereof.

9 . The method according to claim 1 wherein the organic solvent is acetonitrile, tetrahydrofuran, or a combination thereof.

10 . The method according to claim 1 , wherein:
the organic solution comprises (i) a metal salt, having a purity of at least 99.9%, selected from a Sn salt and an Sb salt, (ii) a fluoride dopant selected from HF, NH 4 F, (CH 3 ) 4 NF, CF 3 COOH, SnF 2 , SnF 4 , and combinations thereof, and (iii) an organic solvent selected from an ether, a nitrile, or combinations thereof; and applying the solution to a substrate to form a film comprises forming a film having the thickness of 200 to 700 nm and the RMS surface roughness of <2 nm.

11 . The method according to claim 1 , wherein the film has an RMS surface roughness of ≤1 nm.

12 . The method according to claim 1 , wherein the film has a resistivity of from 1×10 −3 -11×10 −3 ohms·cm.

13 . The method according to claim 1 , wherein the film has a Hall mobility of about 27.5 cm 2 V −1 s −1 .

14 . A metal oxide thin film made according to claim 1 .

15 . The metal oxide thin film according to claim 14 , wherein the metal oxide thin film comprises SnO 2 , Sb:SnO 2 , F:SnO 2 , or (Sb,F):SnO 2 .

16 . The metal oxide thin film of claim 14 , wherein:
the film has a resistivity of from 1×10 −3 -11×10 −3 ohms·cm; the film has a Hall mobility of about 27.5 cm 2 V −1 s −1 ; the film has an RMS surface roughness of ≤1 nm; or a combination thereof.

17 . A method for making a device, comprising:
preparing a solution comprising (i) a metal salt, having a purity of at least 99.9%, the metal salt being selected from a Sn salt, an Sb salt, or combinations thereof, (ii) a fluoride dopant selected from HF, NH 4 F, (CH 3 ) 4 NF, CF 3 COOH, SnF 2 , SnF 4 , and combinations thereof, and (iii) an organic solvent selected from an ether, a nitrile, or combinations thereof; applying the solution to a substrate to form a film on the substrate having a thickness of 200 to 700 nm and an RMS surface roughness of 2 nm or less measured over at least 1×1 μm 2 ; heating the film; and assembling a device comprising the film.

18 . A device made according to claim 17 .

19 . A device comprising a metal oxide thin film and a substrate, wherein the metal oxide thin film comprises SnO 2 , Sb:SnO 2 , F:SnO 2 , or (Sb,F):SnO 2 and is made by a method comprising:
preparing a solution comprising (i) a metal salt, having a purity of at least 99.9%, the metal salt being selected from a Sn salt, an Sb salt, or combinations thereof, (ii) a fluoride dopant selected from HF, NH 4 F, (CH 3 ) 4 NF, CF 3 COOH, SnF 2 , SnF 4 , and combinations thereof, and (iii) an organic solvent selected from an ether, a nitrile, or combinations thereof; applying the solution to a substrate to form a film on the substrate having a thickness of 200 to 700 nm and an RMS surface roughness of 2 nm or less measured over at least 1×1 μm 2 ; and heating the film; and
wherein the film has
a resistivity of from 1×10 −3 -11×10 −3 ohms·cm;
a Hall mobility of about 27.5 cm 2 V −1 s −1 ; or
a resistivity of from 1×10 −3 -11×10 −3 ohms·cm and a Hall mobility of about 27.5 cm 2 V −1 s −1 .

Assignees

• Univ Oregon State

Inventors

• Perkins Cory K
• Keszler Douglas A

Classifications

• C01G19/02 Primary

  Oxides · CPC title

• C01G30/007

  of binary type SbX3 or SbX5 with X representing a halogen, or mixed of the type SbX3X'2 with X,X' representing different halogens · CPC title

• C23C18/1216

  Metal oxides (C23C18/1212 takes precedence) · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01G19/00

  Compounds of tin · CPC title