Method for coating temperature-sensitive substrates with polycrystalline diamond

Patent metadata

Field	Value
Publication number	US-11162172-B2
Application number	US-202016792975-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	Aug 18, 2017
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

A method for coating temperature-sensitive substrates with polycrystalline diamond by a hot-wire CVD method, in which hydrogen and at least one carbon carrier gas are fed into a coating chamber. The fed gases are split at an electrically heated wire in such a way that carbon is formed and deposits on the temperature-sensitive substrate in the form of the diamond modification thereof. The substrate is arranged in the coating chamber, which is at a reduced pressure, and electrical power to electrically heat the wire is adjustable. The method is performed cyclically in respect of the electrical power that is fed to electrically heat the wire. A basic power is fed as lower threshold value for a predetermined time (basic load phase) and is increased for a further predetermined time to a maximum power as an upper threshold value (pulse phase) and is then reduced again to the basic power.

First claim

The invention claimed is:

1. A hot-wire CVD method for coating a substrate with polycrystalline diamond, wherein hydrogen and at least one carbon carrier gas are fed into a coating chamber, wherein the fed gases are split at an electrically heated wire in such a way that carbon is formed, which is deposited on the substrate in the form of diamond, wherein the substrate is arranged in the coating chamber, which is at reduced pressure; and
wherein an electrical power required to electrically heat the wire is adjustable, wherein the method is performed cyclically with respect to the electrical power that is fed in order to electrically heat the wire, wherein a basic power P Bas is fed as lower threshold value for a predetermined time t 1 in a basic load phase, and is increased for a further predetermined time t 2 to a maximum power P max as upper threshold value in a pulse phase, and is then reduced again to the basic power P Bas .

2. The method according to claim 1 , wherein the basic power P Bas during the basic load phase is 50-75% of the power in the pulse phase.

3. The method according to claim 1 , wherein the duration t 1 of a basic load phase lies between 1 μs and 120 s.

4. The method according to claim 1 , wherein the duration t 2 of a pulse phase lies between 1 μs and 60 s.

5. The method according to claim 1 , wherein the method is performed in a total duration tees between 5 and 100 h.

6. The method according to claim 1 , wherein in the pulse phase, the temperature of the wire lies between 2000° C. and 3000° C.

7. The method according to claim 1 , wherein the temperature of the substrate to be coated lies between 500° C. and 600 ° C. in the basic load phase and between 600° C. and 650° C. in the pulse phase.

8. The method according to claim 1 , wherein in the pulse phase, the diamond deposition rate lies between 100 nm/h and 200 nm/h.

9. The method according to claim 1 , wherein the basic power P Bas is 1-15 KW during the basic load phase, and the maximal power Pmax is between 18 and 30 KW during the pulse phase.

10. The method according to claim 1 , wherein the method is performed for a total duration t Ges between 50 and 60 h.

11. The method according to claim 1 , wherein in the pulse phase, the diamond deposition rate is approximately 150 nm/h.

Assignees

• Guehring Kg

Inventors

• Garrn Immo

Classifications

• C23C16/52

  Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)} · CPC title

• C23C16/515

  using pulsed discharges · CPC title

• C23C16/279

  control of diamond crystallography · CPC title

• C23C16/271 Primary

  using hot filaments · CPC title

• C23C16/46

  characterised by the method used for heating the substrate (C23C16/48, C23C16/50 take precedence) · CPC title