A Method for Predicting the Rate of Chemical Vapor Deposition

Abstract

The invention discloses a chemical vapor deposition rate prediction method, which specifically relates to the field of chemical technology research. The specific prediction method is as follows: establishing a finite element reactor model; establishing an energy conservation equation; establishing mass conservation and momentum conservation equations; establishing multi-component diffusion Equation; establishment of gas phase reaction model; determination of main intermediate substances by extreme learning machine model and adhesion coefficient method; establishment of surface reaction model; deposition rate prediction model establishment of the correlation between viscosity coefficient, surface concentration and deposition rate; establishment of intermediate substance viscosity coefficient and its influence Multivariate PLSR model between factors; adhesion coefficient determined from experimental results. The invention combines the simulation technology of machine learning and computational fluid dynamics, which will greatly reduce the dependence of model parameters on human experience, and can accurately determine important intermediate phases and viscosity coefficients through a small number of experiments, and achieve high accuracy and reliability of prediction results. technical effect.

Description

technical field [0001] The invention relates to the technical field of chemical process research, and more specifically, the invention relates to a method for predicting chemical vapor deposition rate. Background technique [0002] Ceramic matrix composites are a type of composite materials that use ceramics as a matrix and various fibers. The ceramic matrix can be high-temperature structural ceramics such as silicon nitride and silicon carbide. It retains the excellent properties of ceramic materials such as high temperature resistance, low density, high specific strength and oxidation resistance, and overcomes the fatal weaknesses of ceramic materials such as high brittleness and poor reliability. As a high-temperature structural material, it can be used in certain high-temperature and harsh environments. Known as "new materials facing the 21st century", it has received more and more attention. [0003] At present, chemical vapor deposition (CVD) is the main method for pr...

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Problems solved by technology

[0007] 1. Before the gas-phase substances reach the surface of the deposition substrate, the precursor will generate a large amount of mesophase substances. It is difficult to accurately judge which mesophases are the main contributors to the deposited solid phase and which mesophases control the deposition rate only by the concentration of the gas-phase components. The main factors lead to the selection of the mesophase is very empirical and has a large error;

[0008] 2. Even if the main mesophase is determined, because various mesophases compete to occupy surface vacancies during the deposition process, and these relationships may change with changes in temperature, pressure and the concentration of each component, only relying on the existing It is difficult to determine the influence of these factors on the viscosity coefficients of various main mesophases by technology, and the viscosity coefficients currently used are mostly measured under non-sedimentary conditions. It is doubtful whether it can be directly applied to the actual depositional environment. This is also one of the reasons for the poor universality of the established model

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