CN106835065A - A kind of Nano diamond silane surface vacuum pyrolysis depositing device - Google Patents

Abstract

A kind of Nano diamond silane surface vacuum pyrolysis depositing device, including：Mechanical pump (1), diffusion pump (2), four-way valve (3), vacuum tube furnace (4), quartz ampoule (5), objective table (7), silane air inlet (8), argon inlet mouthful (9), flowmeter (10), compound vacuum gauge (11), vent valve (12).Nano diamond surface impurity functional group pyrolysis absorption under high vacuum state, between silane gas are fully infiltrated into Nano diamond powder at room temperature, unimolecule or polymolecular saturation adsorption layer is formed with Nano diamond surface dangling bond, and disperse is in Nano diamond surface.Subsequent adsorbate inert gas pyrolysis in situ, Nano diamond surface forms atom level silicon cladding.The purification that the present invention realizes Nano diamond preserves problem, it is possible to resolve purchase ALD plating equipments are expensive, and coating technology difficulty is big, high cost, efficiency are low, and Nano diamond high-volume Si atom plating industrialization problem.

Description

Vacuum pyrolysis deposition equipment for silane on nano-diamond surface

technical field

The application relates to the field of PDC tool material manufacturing, in particular to a vacuum pyrolysis deposition device for silane on the surface of nano-diamond.

Background technique

At present, most of the nano-diamonds used at home and abroad are prepared by the detonation method. Nano-diamond not only has the general characteristics of diamond, but also has the small size effect of nano-materials and a large specific surface, especially the nano-diamond synthesized by the detonation method contains more dislocations and lattice distortions, so the detonation method is produced The nano-diamond has a high surface activity, and a large number of oxygen-containing functional groups are adsorbed on its surface, mainly including hydroxyl, carboxyl, carbonyl, ether, ester, and some nitrogen-containing groups. Therefore, the purification of the surface of nano-diamonds and the storage after purification have become the key technical issues to be solved in the downstream application of nano-diamonds.

In order to solve the above problems, firstly, the nano-diamond is purified under a high vacuum state to desorb a large amount of oxygen-containing, nitrogen-containing, and Cl-containing functional groups adsorbed on the surface. After cooling to room temperature, introduce silane gas into the reaction chamber, and fully infiltrate between the stacked nano-diamond powder under negative pressure. Part of the precursor molecules react with the dangling bonds on the surface of the nano-diamond to form a monomolecular or multi-molecular saturated adsorption layer, and the excess gas molecules are uniformly dispersed around the nano-diamond. Then an inert protective gas is introduced to allow the adsorbate to be pyrolytically deposited in situ at a certain temperature. Since the above-mentioned adsorption-pyrolysis reaction is a self-limiting reaction controlled by the total amount of gas introduced into the surface adsorption layer, it can promote the two-dimensional growth of the silicon coating along the surface to form a quasi-atomic coating.

Since silane is a flammable and dangerous gas, to realize silane pyrolytic deposition of quasi-atomic silicon coating on the surface of nano-diamond, the equipment deposition conditions and safe use conditions are relatively harsh, which cannot be achieved by general chemical vapor deposition equipment. Therefore, it is necessary to develop a dedicated nano-diamond vacuum silane pyrolysis deposition equipment.

Contents of the invention

The invention provides a vacuum pyrolysis deposition device for purifying the nano-diamond surface and realizing quasi-atomic silicon coating. Specifically, preferably, the equipment includes: a mechanical pump, a diffusion pump, a four-way valve, a vacuum tube furnace, a quartz tube, a stage, a silane gas inlet, an argon gas gas inlet, a flow meter, a composite vacuum gauge, Air release valve; the mechanical pump is connected to the diffusion pump; the diffusion pump is connected to the first pass of the four-way valve; the composite vacuum gauge is connected to the first pass of the four-way valve connected, the third port of the four-way valve is connected to the silane gas inlet, the second port of the four-way valve is connected to the argon gas inlet, and the fourth port of the four-way valve Link to one end of the quartz tube in the vacuum tube furnace; the other end of the quartz tube is connected to the outside with a vent valve; the quartz tube is provided with a stage capable of holding nano-diamonds;

Its beneficial effect is that it fully infiltrates between the stacked nano-diamond powder under negative pressure to realize the adsorption-pyrolysis reaction, which is a self-limiting reaction controlled by the total amount of gas introduced into the surface adsorption layer, thus promoting silicon coating. Two-dimensional growth along the surface forms a quasi-atomic coating.

The mechanical pump is connected with the diffusion pump by a low vacuum tube, and the beneficial effect is that the low vacuum is drawn first.

The joint of the composite vacuum gauge and the first pass of the four-way valve is provided with a vacuum valve between the composite vacuum gauge and the first pass of the four-way valve; Valve control, there is a flow meter between the second port of the four-way valve and the silane gas cylinder, the third port of the four-way valve is connected to the argon gas cylinder with a DN8 vacuum hose, and an argon valve is arranged between, and the four-way The fourth pass of the valve is connected with the quartz test tube in the vacuum tube furnace with a high vacuum tube, and a reaction valve is arranged between the fourth pass of the four-way valve and the quartz test tube. The beneficial effect is that the nano-diamond is purified and treated in a high vacuum state to desorb a large amount of oxygen-containing, nitrogen-containing and Cl-containing functional groups adsorbed on the surface. After cooling to room temperature, introduce silane gas into the reaction chamber, and fully infiltrate between the stacked nano-diamond powder under negative pressure.

The measuring range of the composite vacuum gauge is 0-10-6Pa, and its beneficial effect is that the vacuum degree in the high vacuum system is measured, and the ultimate vacuum is ≤1x10-6Pa.

The high-vacuum tube is connected to the quartz test tube with a ring groove surface flange connection; the quartz test tube is connected to the vent valve with a sealed sleeve structure, and its beneficial effect is that its sealing performance can be effectively guaranteed through the sealing of several sealing rings. The high-vacuum environment required for deposition effectively avoids potential safety hazards when using silane gas. The movable clamp structure is designed. When unloading and placing objects, you only need to unscrew the clamp and remove the end cover, then the quartz stage can be taken out or built in. This not only facilitates the placement and removal of samples, but also ensures that the nano-diamond powder can be spread evenly and evenly.

The vacuum valve, silane valve, argon valve, and reaction valve are connected to the four-way valve in the same way, and are connected by stainless steel vacuum clamps. The beneficial effect is to ensure the high vacuum environment required for deposition. The beneficial effect is that some precursor molecules react with dangling bonds on the surface of the nano-diamond to form a monomolecular or multi-molecular saturated adsorption layer, and redundant gas molecules are evenly dispersed around the nano-diamond. Then the inert protective gas is introduced and under certain temperature conditions, the adsorbate is pyrolyzed in situ to form a silicon coating on the surface of the nano-diamond. The quasi-atomic silane coating layer is uniformly coated, and the thickness is about 0.5nm-10nm.

The venting valve is connected to the flange of the ring groove surface by welding, which has the beneficial effect of ensuring the high vacuum environment required for deposition and effectively avoiding potential safety hazards in the use of silane gas.

The size of the quartz test tube is As a reaction chamber for pyrolytic deposition of silane, the beneficial effect is to ensure that the nano-diamond is heated evenly, the deposition temperature is continuously adjustable from about 300°C to 650°C, and the stability of the temperature zone is ±1°C.

Description of drawings

Fig. 1 is the assembly schematic diagram of silane vacuum pyrolysis deposition equipment on nano-diamond surface;

Fig. 2 is a schematic diagram of the structure of the end seal set;

Figure 3 is a transmission electron microscope image of silicon atom-coated nano-diamonds;

detailed description

A silane vacuum pyrolysis deposition equipment, comprising a mechanical pump 1 and a vacuum pump 2, the silane inlet 7, the protective gas argon inlet 8 are connected to the quartz tube 5 in the vacuum tube furnace 4 through a four-way valve 3, so as to ensure High vacuum environment required for silane plating. The nano-diamonds are placed on the stage 6 inside the quartz tube 5, and the nano-diamonds are purified in a high-vacuum, high-temperature environment to desorb a large number of functional groups containing oxygen, nitrogen, and Cl that are adsorbed on the surface. After cooling to room temperature, the silane gas is introduced into the reaction chamber, and the flow meter 9 controls the content of the silane so that it can fully infiltrate between the accumulated nano-diamond powder under negative pressure. Part of the silane gas reacts with the dangling bonds on the nano-diamond surface to form a monomolecular or multi-molecular saturated adsorption layer, which is uniformly dispersed around the nano-diamond. Then, the protective gas argon is introduced from the argon gas inlet 8 so that the adsorbate is pyrolyzed in situ to form a silicon coating on the surface of the nano-diamond. Wherein, the degree of vacuum is measured by a compound vacuum gauge 10 .

When working, the system needs to be vacuumed by the mechanical pump 1 first, and when the vacuum degree reaches below 5Pa, the diffusion pump 2 is turned on to make the system reach a high vacuum degree, and the vacuum degree reaches about 8×10-3Pa～1×10-4Pa You can start heating the system; heat the molybdenum boat and the reaction chamber loaded with nano-diamonds, and the temperature rises to 400 ° C ~ 700 ° C, and the functional group dangling bonds on the surface of the nano-diamonds are broken under high vacuum and high temperature, and then the temperature Cool down to room temperature; first feed silane gas, the intake time is 1s~40s, the flow rate of silane gas is controlled by flow meter 9, the flow rate is 1sccm~1000sccm, the exposure time of silane gas in the deposition chamber is 1min~50min, so that silane is adsorbed on Diamond surface; the argon gas flow time is 10-80s, the gas flow rate of argon gas is 1ml/min-20ml/min, and the aeration time is 5s-40s; after aeration, start heating, heating to 400℃～600℃, under the high temperature of silane When decomposed, the silicon atoms bind to the diamond surface with dangling bonds. At this time, atomic-level silicon is attached to the surface of the nano-diamond. Finally, the vent valve 11 was opened, and the remaining silane gas in the experiment was dispersed out of the reaction chamber with argon gas.

Fig. 3 is a transmission electron microscope image of nano-diamond after silane plating. The figure shows that the silicon atom coating on the surface of the nano-diamond is at the atomic level, with a size of about 5nm, which realizes the atomic-level coating of silicon on the surface of the nano-diamond.

Claims (1)

1. A nano-diamond surface silane vacuum pyrolysis deposition equipment is characterized in that said equipment comprises: mechanical pump (1), diffusion pump (2), four-way valve (3), vacuum tube furnace (4), quartz Tube (5), stage (6), silane gas inlet (7), argon gas inlet (8), flow meter (9), composite vacuum gauge (10), air release valve (11), ring groove flange (12); the mechanical pump (1) is connected to the diffusion pump (2); the diffusion pump (2) is connected to the first pass of the four-way valve (3); the Described composite vacuum gauge (10) is connected with the first pass of described four-way valve (3), and the third pass of described four-way valve (3) is connected with described silane inlet (7), The second pass of the four-way valve (3) is connected with the argon inlet (8), the fourth pass of the four-way valve (3) is connected with the quartz in the vacuum tube furnace (4). One end of the tube (5) is connected; the other end of the quartz tube (5) is connected with the outside with an air release valve (11); the quartz tube (5) is provided with a stage (6) that can hold nano-diamonds; The nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 1, wherein the mechanical pump (1) is connected with the diffusion pump (2) with a low vacuum tube; Nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 1, is characterized in that, a vacuum valve is provided between the first pass of the composite vacuum gauge (10) and the four-way valve (3); The second pass of the four-way valve and the silane gas cylinder are controlled by a high vacuum tube with a silane valve, a flow meter (9) is arranged between the second pass of the four-way valve and the silane gas cylinder, and the third of the four-way valve Pass and the argon gas inlet are connected with DN8 vacuum rubber hose, and an argon valve is arranged between them, and the fourth pass of the four-way valve is connected with the quartz tube (5) in the vacuum tube furnace (4) with a high vacuum tube , a reaction valve is arranged between the fourth pass of the four-way valve and the quartz tube (5); The nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 3, characterized in that, the range of the composite vacuum gauge (10) is 0-10-6Pa; The nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 1, is characterized in that, described high-vacuum tube and quartz tube (5) are connected to each other with annular groove surface flange (12); Quartz tube (5) and The deflation valve (11) is connected with a ring groove surface flange; The vacuum pyrolytic deposition equipment for silane on nano-diamond surface according to claim 3, characterized in that, the vacuum pumping valve, the silane valve, the argon valve, the reaction valve and the four-way valve Connection, the connection method is the same, using stainless steel vacuum clamp connection; The nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 5 is characterized in that the air release valve is connected to the ring groove surface flange (12) by welding; Nano-diamond surface silane vacuum pyrolysis deposition equipment according to claim 1, is characterized in that, described quartz tube (5) size is It serves as the reaction chamber for the pyrolytic deposition of silane.