Low resistance indium oxide coatings

• US 4,201,649 A
• Filed: 11/29/1978
• Issued: 05/06/1980
• Est. Priority Date: 11/29/1978
• Status: Expired due to Term

• Current Assignee: PPG Industries Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Incorporated (Nouryon BV)
• Inventors: Gillery, F. Howard
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Leader, William
• Application Number:
  US05/964,765
• Time in Patent Office: 524 Days
• Field of Search: 204/192 P, 204/192 SP
• US Class Current: 204/192.12
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 2217/211 SnO2
• CPC Class Codes: C03C 2217/215 In2O3
• CPC Class Codes: C03C 2217/229 Non-specific enumeration
• CPC Class Codes: C03C 2217/231 In2O3/SnO2
• CPC Class Codes: C03C 2218/155 by reactive sputtering
• CPC Class Codes: C23C 14/0036 Reactive sputtering

Abstract

A method is disclosed for making low resistance thin indium oxide films by first depositing a thin primer layer of indium oxide at low temperature before heating to deposit the bulk of the conductive layer of indium oxide by cathode sputtering.

Claims

1. In a method for depositing a transparent electroconductive coating consisting essentially of the oxide of at least one metal having an atomic number between 48 and 51 comprising the steps of supporting a substate in an atmosphere comprising an inert gas and sufficient oxygen to effect oxide formation at a pressure of less than about 10^-1 Torr, heating the substrate, and cathode sputtering a metallic target to deposit said oxide onto said substrate until a coating of desired thickness is formed, the improvement which comprises carrying out the cathode sputtering in at least two steps at substantially different temperatures whereby

a. a thin layer of oxide constituting the minor portion of the final oxide layer is deposited at a temperature of T₁ ;

b. the deposition is interrupted while the substrate is heated; and

c. subsequently, the major portion of the final oxide layer is deposited at a temperature T₂

wherein T₁ which is less than about 200°

F. (about 94°

C.) is substantially lower than T₂ which is at least about 400°

F. (about 204°

C.).

2. The method according to claim 1, wherein said oxide is a mixture comprising from about 80 to 99 percent indium oxide and from about 1 to 20 percent tin oxide.

3. The method according to claim 2, wherein the film deposited prior to heating said substrate is at least about 20 Angstroms thick and the total thickness of the sputtered coating is less than 800 Angstroms.

4. The method according to claim 3, wherein the film deposited prior to heating said substrate is at least about 30 Angstroms thick and the total thickness of the sputtered coating is from about 200 to 800 Angstroms.