CN1067119C - Method and apparatus for large area high-speed thermal filament chemical vapor deposition of diamond - Google Patents

Abstract

The present invention relates to a method for the hot filament chemical vapor deposition of diamond with a large area at a high speed. The usual proportion of hydrogen and methane is adopted, the methane accounts for 1 to 1.5% of total flow, the flow of mixed gases is from 10 to 200 SCCM/cm<2>, and the temperature of a reacting region maintains from 2000 to 2600 DEG C. The present invention is characterized in that the hydrogen is aligned to tungsten filaments and the methane is aligned to a gap between the two tungsten filaments to be uniformly blown into the reacting region. The present invention causes the service life of the tungsten filaments to be extended greatly.

Description

A method and equipment for large-area high-speed hot wire chemical vapor deposition of diamond

The invention relates to chemical vapor deposition diamond technology, and in particular provides a method for growing diamond in a large area and at a high speed using the hot wire chemical vapor deposition technology.

Hot-filament chemical vapor deposition (HFCVD) is one of the most widely used techniques for vapor growth of diamond. However, it also has some unresolved technical issues. For example, the life of the heating wire is not long enough, which affects the production efficiency. In the existing HFCVD process, methane is usually mixed with hydrogen first, and then sent between the tungsten wire heaters. The mixed gas passes through the heating wire to form a high temperature The area is heated by intense radiation and convection. The direct contact between methane and tungsten wire at high temperature leads to the carbonization of tungsten wire, which aggravates the deformation, surface delamination and cracking of tungsten wire. When using hydrodynamic strengthening technology to increase the growth rate of HFCVD diamond, the problem of tungsten wire life becomes more prominent.

The object of the present invention is to provide a hot wire chemical vapor deposition method and equipment capable of growing diamonds in a large area, and the service life of the tungsten wire of the equipment can be greatly improved.

The invention provides a method for large-area high-speed hot wire chemical vapor deposition of diamond, adopting the usual ratio of hydrogen and methane, methane accounts for 1-1.5% of the total flow, and the mixed gas flow is 10-200SCCM/cm ² ; keep the reaction The final temperature is 2000-2600°C, and it is characterized in that: the hydrogen gas is directed at the tungsten wire, and the methane gas is directed at the gap between the two tungsten wires and blown into the reaction area evenly. Hydrogen can also be mixed in the methane gas sent between the two tungsten wires, and the amount of hydrogen accounts for less than 70% of the total amount of hydrogen used. The invention can not only reduce the carbonization tendency of the tungsten wire, but also can realize the uniform feeding of the reactant gas, so as to realize the large-area and high-speed growth of diamond.

The present invention also provides a kind of equipment dedicated to the large-area and high-speed hot wire chemical vapor deposition diamond of the above method, including a vacuum system, a reaction chamber with a hot wire heater, electric control and other parts, characterized in that: A gas distributor is arranged above the device, and the gas distributor is divided into three closed chambers: upper, middle and lower;

The upper chamber (1) is a methane gas chamber, which is provided with a methane gas inlet (11), and the bottom is connected with 5 to 100 long and narrow methane gas passages (12) that pass through the middle and lower chambers (2) (3) and are arranged in parallel. ).

The middle chamber (2) is a hydrogen chamber, which is provided with a hydrogen inlet (21), and the bottom is connected with the methane gas passage (12) with 6 to 101 long and narrow hydrogen passages (22) passing through the lower chamber (3);

The lower chamber (3) is a water-cooled chamber, which is provided with a water inlet (31) and a water outlet (32); the hot wire (4) is facing the hydrogen channel (22).

The above-mentioned methane gas channel (12) can also protrude outside the device wall, and the hot wire (4) is trapped between two adjacent methane gas channels (12), and the distance between the outlet of the hydrogen gas channel (22) and the hot wire (4) is 3-3. 5mm.

The present invention will be described in detail below in conjunction with the accompanying drawings through the embodiments.

Accompanying drawing 1 is the structural representation of gas distributor

Accompanying drawing 2 is the gas distributor structure A-A sectional view

Accompanying drawing 3 is the B-B sectional view of gas distributor structure

Example 1

The gas distributor structure of the equipment used is shown in the attached figure. The diamond film is deposited by HFCVD. In the gas distributor used, there are 11 hydrogen channels, each with a width of 1 mm and a length of 110 mm; 10 methane channels, each with a width of 1 mm and a length of 100 mm. The growth area is 100×100mm.

The distance from the outlet plane of the hydrogen channel to the plane of the tungsten wire heater is 3-5mm. The total gas flow rate is 20SLM. The diameter of the tungsten wire is 2mm, and the distance between the tungsten wires is 10mm. The distance between the sample and the tungsten wire heater is 5-20mm. The heating temperature of tungsten wire is 2200～2400℃. The continuous heating life of tungsten wire exceeds 1000 hours, and the cumulative life of tungsten wire heating for multiple times exceeds 600 hours. The uniform and high-quality growth rate of the diamond film can reach above 40μm/h.

Example 2

The diamond film was deposited by HFCVD. In the gas distributor used, there were 21 hydrogen channels, each with a width of 1 mm and a length of 210 mm; 20 methane channels, each with a width of 1 mm and a length of 200 mm. The growth area is 200×200mm.

The distance from the outlet plane of the hydrogen channel to the plane of the tungsten wire heater is 3-5mm. The total gas flow rate is 20SLM. The diameter of the tungsten wire is 2mm, and the distance between the tungsten wires is 10mm. The distance between the sample and the tungsten wire heater is 5-20mm. The heating temperature of tungsten wire is 220-2400℃. The continuous heating life of tungsten wire exceeds 1000 hours, and the cumulative life of tungsten wire heating for multiple times exceeds 600 hours. The uniform and high-quality growth rate of the diamond film can reach above 40μm/h.

Claims (4)

1. the method for a large area high-speed thermal filament chemical vapor deposition of diamond adopts the common hydrogen and the ratio of methane, and methane accounts for the 1-1.5% of total flux, mixed gas flow 10～200SCCM/cm ²Keep reaction zone temperature at 2000～2600 ℃, it is characterized in that: hydrogen is aimed at tungsten filament, and the neutral gear that methane gas is aimed between two tungsten filaments is blown into reaction zone equably.

2. by the method for the described large area high-speed thermal filament chemical vapor deposition of diamond of claim 1, it is characterized in that: the amount that can also be mixed with hydrogen, hydrogen between two tungsten filaments in the methane gas of sending into accounts for the total consumption of hydrogen below 70%.

3. one kind is exclusively used in claim 1, the equipment of 2 described large area high-speed thermal filament chemical vapor deposition of diamond, comprise vacuum system, band hot wire heater's reaction chamber, part such as automatically controlled, it is characterized in that: a gas distributor is set above the hot wire heater, and gas distributor is divided into three airtight chambers, upper, middle and lower;

Last chamber (1) is the methane air chamber, is provided with methane gas inlet (11), and the bottom is connected in 5～100 long and narrow passing of be arrangeding in parallel, the methane gas passage (12) of two Room (2) (3) down.

Middle chamber (2) is a hydrogen chamber, is provided with a hydrogen inlet (21), the alternate hydrogen passage (22) that is connected to chamber (3) under 6～101 long and narrow passing with methane gas passage (12) in bottom;

Following chamber (3) is the water cooling chamber, is provided with water-in (31) and water outlet (32); Heated filament (4) is over against hydrogen passage (22).

4. by the described large area high-speed thermal filament chemical vapor deposition of diamond equipment of claim 3, it is characterized in that: described methane gas passage (12) protrudes from outside the wall, heated filament (4) is absorbed between the adjacent two methane gas passages (12), and hydrogen passage (22) exports apart from heated filament (4) spacing at 3～5mm.

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