Highly twinned, oriented polycrystalline diamond film and method of manufacture thereof

Patent metadata

Field	Value
Publication number	US-10373725-B2
Application number	US-201514817704-A
Country	US
Kind code	B2
Filing date	Aug 4, 2015
Priority date	Nov 6, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

In a method of chemical vapor deposition (CVD) growth of a polycrystalline diamond film in a CVD reactor, a gas mixture of gaseous hydrogen and a gaseous hydrocarbon is introduced into the CVD reactor. A plasma formed from the gas mixture is maintained above a surface of a conductive substrate disposed in the CVD reactor and causes a polycrystalline diamond film to grow on the surface of the conductive substrate. A temperature T at the center of the polycrystalline diamond film is controlled during growth of the polycrystalline diamond film. The CVD grown polycrystalline diamond film includes diamond crystallites that can have a percentage of orientation along a [110] diamond lattice direction≥70% of the total number of diamond crystallites forming the polycrystalline diamond film.

First claim

The invention claimed is:

1. A method of chemical vapor deposition (CVD) growth of a free standing polycrystalline diamond film in a CVD reactor, the free standing polycrystalline diamond film having a thickness ≥100 micron and a percentage of orientation along a [110] diamond lattice direction ≥70% of the total number of diamond crystallites forming the polycrystalline diamond film, the method comprising:
(a) igniting and maintaining a plasma above a surface of a conductive substrate disposed in the CVD reactor in the presence of flow of a gas mixture of gaseous hydrogen (H) and a gaseous hydrocarbon (GH) into the CVD reactor, wherein the CVD reactor is maintained at a pressure (P) 100 torr<P≤350 torr during growth of the polycrystalline diamond film, whereupon the maintained plasma forms the polycrystalline diamond film on the surface of the conductive substrate; and
(b) concurrent with step (a), controlling a temperature T at the center of the diamond film such that 1000° C.≤T≤1300° C.

2. The method of claim 1 , wherein the flow of the gas mixture includes:
a flow of GH (F GH ) of 10 mL/min≤F GH ≤200 mL/min; and
a flow of H (F H ) of 1000 mL/min≤F H ≤3500 mL/min.

3. The method of claim 1 , wherein the gas mixture is introduced into the CVD reactor at a flow rate of ≥1000 mL/min.

4. The method of claim 1 , wherein a concentration of the gaseous hydrocarbon (C GH ) in the mixture is 0.5%≤C GH ≤5%.

5. The method of claim 1 , wherein GH is methane (CH 4 ).

6. The method of claim 5 , wherein a concentration of methane (C CH4 ) in the mixture is 1-4%.

7. The method of claim 1 , further including forming the plasma in step (a) by introducing microwave energy into the CVD reactor, wherein a power of the microwave energy introduced into the CVD reactor is between 15 k watts-30 k watts.

8. The method of claim 7 , wherein the microwave energy is introduced into the CVD reactor at a frequency of 915 Mhz.

9. The method of claim 1 , wherein the mixture further includes at least one of the following: nitrogen, boron, an oxygen containing gas, and an inert gas.

10. The method of claim 1 , wherein the polycrystalline diamond film is grown by one of the following techniques: microwave-plasma CVD, DC-Arc Jet plasma CVD, hot-filament CVD, and hydrocarbon (e.g., acetylene) torch CVD.

Assignees

• Ii Vi Inc

Inventors

• Xu Wen-Qing
• Liu Chao
• Kraisinger Charles J
• Tanner Charles D
• Currier Ian
• Sabens David
• Eissler Elgin E
• Anderson Thomas E

Classifications

• H01B1/04 Primary

  mainly consisting of carbon-silicon compounds, carbon or silicon · CPC title

• C01B32/25

  Diamond · CPC title

• C23C16/274 Primary

  using microwave discharges · CPC title

• C30B29/04

  Diamond · CPC title

• C23C16/276

  using plasma jets · CPC title