# US 10,373,725 B2 · Highly twinned, oriented polycrystalline diamond film and method of manufacture thereof

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- Number: US 10,373,725 B2
- Document ID: US10373725B2
- Status: Granted
- Kind: B2
- Application number: 14/817,704
- Filed: 2015-08-04
- Published: 2016-05-12
- Granted: 2019-08-06
- Earliest claimed: 2014-11-06
- Assignees: II-VI Incorporated
- Applicants: II-Vi Incorporated
- Inventors: Wen-Qing Xu; Chao Liu; Charles J. Kraisinger; Charles D. Tanner; Ian Currier; David Sabens; Elgin E. Eissler; Thomas E. Anderson
- Web page: https://patentgrep.com/patent/US10373725B2

## CPC

- H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon
- C01B 32/25: Diamond
- C01B 32/26: Preparation (by using ultra-high pressure B01J3/06; by crystal growth C30B29/04)
- C23C 16/274: {using microwave discharges}
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 1)

The method of claim 1, wherein GH is methane (CH4).

### Claim 6 (depends on 5)

The method of claim 5, wherein a concentration of methane (CCH4) in the mixture is 1-4%.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 7)

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

### Claim 9 (depends on 1)

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.

### Claim 10 (depends on 1)

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.