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CN-121992367-A - Simple preparation method of large-size high-quality self-supporting diamond thick film

CN121992367ACN 121992367 ACN121992367 ACN 121992367ACN-121992367-A

Abstract

The invention belongs to the technical field of diamond film preparation, and relates to a simple large-size high-quality self-supporting diamond thick film preparation method which comprises the steps of carrying out surface pretreatment on a large-size molybdenum block by using diamond micro powder, removing surface impurities, then carrying out plasma treatment on the surface of the large-size molybdenum block by using a CVD device, carrying out CVD growth, and after repeating partial steps of the CVD growth according to the thickness of a needed polycrystalline film, starting methane accounting for 2-3vol% of mixed gas under the conditions of 850-950 ℃, 5-8slm hydrogen and 4.5-5.5kpa, and utilizing the CVD device to grow a nanocrystalline layer with the thickness of 0.3-1mm, thereby preparing the high-quality diamond film. The preparation method is simple and convenient, can be repeatedly used for a plurality of times, can reduce the use cost of the substrate at the later stage, and realizes the high film-finishing rate and low thermal shock stress of the self-supporting thick film, thereby improving the quality of the diamond film.

Inventors

  • LI LI
  • GUO MINGMING
  • LI MINGZHU
  • ZHANG TONGYU

Assignees

  • 河南飞孟金刚石股份有限公司

Dates

Publication Date
20260508
Application Date
20260224

Claims (5)

  1. 1. A simple preparation method of a large-size high-quality self-supporting diamond thick film is characterized by comprising the following steps: 1) Surface pretreatment, namely grinding the large-size molybdenum block by using diamond micro powder to remove surface impurities, and then carrying out plasma treatment on the surface of the large-size molybdenum block by using CVD equipment; 2) CVD growth: 21 Under the conditions of 850-950 ℃ hydrogen of 5-8slm, argon of 2-4slm and pressure of 3.5-5.5kpa, starting methane accounting for 2-3vol% of the mixed gas, forming a carbon molybdenum compound layer with the thickness of 100-200nm on the surface of a large-size molybdenum block by using CVD equipment; 22 Under the conditions of 800-850 ℃, 5-8slm of hydrogen, 2-4slm of argon and 3.5-5.5kpa of pressure, using 3-5vol% of methane and 0.2-1vol% of oxygen which are contained in the mixed gas, growing a compact nano diamond and amorphous carbon mixture layer with the thickness of 200-300nm on the surface of a carbon molybdenum compound layer by using a CVD device, then gradually reducing the carbon flow to 0, cooling to 300 ℃ at the speed of 4 ℃ per minute, shutting down, and performing surface treatment by using diamond micro powder to remove redundant carbon impurities; 23 Under the conditions of 850-950 ℃ hydrogen with 5-8slm and pressure of 3.5-5.5kpa, starting methane accounting for 2-3vol% of the mixed gas, forming a nano crystal layer with the thickness of 100-200nm on the surface of the compact nano diamond and amorphous carbon mixture layer by using a CVD device, and performing surface treatment by using diamond micro powder after shutdown; 24 Under the conditions of 800-850 ℃ and 5-8slm hydrogen and 4.0-5.5kpa pressure, starting 3-5vol% of methane and 0.2-1vol% of oxygen in the mixed gas, continuously growing a layer of compact nano diamond and amorphous carbon mixture layer with the thickness of 100-200nm on the surface of the nano crystal layer by using a CVD device, gradually reducing the carbon flow to 0, and performing surface treatment by using diamond micro powder after shutdown; 3) Repeating the steps 23) -24) for 2 to 5 times according to the thickness of the needed polycrystalline film, starting methane accounting for 2-3vol% of the mixed gas under the conditions of 850-950 ℃ and 5-8slm of hydrogen and 4.5-5.5kpa of pressure, and growing a nanocrystalline layer with the thickness of 0.3-1mm on the surface of the compact nano diamond and amorphous carbon mixture layer generated in the step 24) by using a CVD device, so as to prepare the high-quality diamond film.
  2. 2. The simple large-size high-quality self-supporting diamond thick film manufacturing method according to claim 1, wherein the nominal maximum linear size of the large-size molybdenum block is 2-4 inches, and the height is 40-100 mm.
  3. 3. The method for preparing a simple large-size high-quality self-supporting diamond thick film according to claim 1, wherein in the step 1) and the step 2), the particle size of the diamond micro powder is 0.5-1 μm.
  4. 4. The method for preparing a simple large-size high-quality self-supporting diamond thick film according to claim 1, wherein in the step 1), the plasma treatment is performed under the condition of 850-900 ℃ by using 0.2-2vol% of oxygen, 5-8slm of hydrogen and 2-4slm of argon in mixed gas.
  5. 5. The method for preparing a simple large-size high-quality self-supporting diamond thick film according to claim 4, wherein in the step 1), the plasma treatment time is 5-10 hours.

Description

Simple preparation method of large-size high-quality self-supporting diamond thick film Technical Field The invention belongs to the technical field of diamond film preparation, and particularly relates to a simple preparation method of a large-size high-quality self-supporting diamond thick film. Background In the process of preparing the high-quality diamond film, a large-size molybdenum block is taken as one of key factors of a base material, and the surface treatment and film growth technology directly influence the uniformity, the adhesive force and the mechanical property of the film. Along with the continuous expansion of the application field of the diamond film, the requirements on the film quality are also higher and higher. Therefore, how to realize the growth of the high-quality diamond film on the large-size molybdenum block becomes an important research direction in the technical field of the preparation of the diamond film. Currently, in order to solve the problem of diamond film growth on large-sized molybdenum blocks, the main measures to be taken include conventional Chemical Vapor Deposition (CVD) methods, physical Vapor Deposition (PVD) methods, and the like. For example, a diamond film can be grown on the surface of a molybdenum block by a conventional CVD method, but the method tends to have problems of slow film growth rate, unstable film quality, high equipment cost, etc., while the PVD method can improve the film growth rate, but the film adhesion and uniformity tend to be inferior to the CVD method. Although the prior art improves the growth quality of diamond films to some extent, there are still some problems and disadvantages. Firstly, the traditional CVD method has low growth speed, which results in low production efficiency, and the film quality is influenced by various factors, so that the large-scale and high-quality diamond film production is difficult to realize, secondly, the PVD method has high growth speed, but the film has poor adhesive force and uniformity, so that the application of the PVD method in the high-performance application field is limited, and in addition, the existing technical scheme has certain limitation in practical application, so that the quality requirements of the diamond film under different production conditions are difficult to meet. Therefore, a novel high-quality diamond film growth method on a large-size molybdenum block is developed, and the method has important practical significance and application value. Disclosure of Invention Aiming at the problems existing in the prior art, the invention firstly provides a simple preparation method of a large-size high-quality self-supporting diamond thick film so as to prepare a diamond film with good uniformity, no crack and good mechanical property, and the growth of the high-quality diamond film on a large-size molybdenum block can be realized with lower cost. In order to achieve the above object, the present invention provides a simple method for preparing a large-size high-quality self-supporting diamond thick film, comprising the following steps: 1) Surface pretreatment, namely grinding the large-size molybdenum block by using diamond micro powder to remove surface impurities, and then carrying out plasma treatment on the surface of the large-size molybdenum block by using CVD equipment; 2) CVD growth: 21 Under the conditions of 850-950 ℃ hydrogen of 5-8slm, argon of 2-4slm and pressure of 3.5-5.5kpa, starting methane accounting for 2-3vol% of the mixed gas, forming a carbon molybdenum compound layer with the thickness of 100-200nm on the surface of a large-size molybdenum block by using CVD equipment; 22 Under the conditions of 800-850 ℃, 5-8slm of hydrogen, 2-4slm of argon and 3.5-5.5kpa of pressure, using 3-5vol% of methane and 0.2-1vol% of oxygen which are contained in the mixed gas, growing a compact nano diamond and amorphous carbon mixture layer with the thickness of 200-300nm on the surface of a carbon molybdenum compound layer by using a CVD device, then gradually reducing the carbon flow to 0, cooling to 300 ℃ at the speed of 4 ℃ per minute, shutting down, and performing surface treatment by using diamond micro powder to remove redundant carbon impurities; 23 Under the conditions of 850-950 ℃ hydrogen with 5-8slm and pressure of 3.5-5.5kpa, starting methane accounting for 2-3vol% of the mixed gas, forming a nano crystal layer with the thickness of 100-200nm on the surface of the compact nano diamond and amorphous carbon mixture layer by using a CVD device, and performing surface treatment by using diamond micro powder after shutdown; 24 Under the conditions of 800-850 ℃ and 5-8slm hydrogen and 4.0-5.5kpa pressure, starting 3-5vol% of methane and 0.2-1vol% of oxygen in the mixed gas, continuously growing a layer of compact nano diamond and amorphous carbon mixture layer with the thickness of 100-200nm on the surface of the nano crystal layer by using a CVD device, gradually reducing th