| In 21 century, developing new energy and renewable clean energy is one of the most decisive influence technology. Solar photovoltaic technology is the fastest developing and the most dynamic renewable energy technology in recent years. Film solar cell is the second generation solar cell, it is the main way to cut costs of solar cells and development trends, and Amorphous-Silicon Thin Film is ideal for high efficiency low-cost materials of photovoltaic solar cells.There is very close relationship between the structures and properties of the film and it's preparation process. Present the view that the Amorphous-Silicon thin film prepared by glow discharge gets the best quality. At home and abroad the researching on thin film growth is mainly based on the experiments of the film's technical characteristics, optimization of process and structure parameters. However,there're great advantages in computer digital simulation in modeling and calculation, that can help designers and technologist find design problems by providing a basis for optimum structural design and processing parameter. This paper studies the growth of amorphous silicon thin film in the PECVD (Plasma-Enhanced Chemical Vapor Deposition) equipment by using computer simulation methods. The main contents are as follows:1. The flow field in Plasma Enhanced Chemical Vapor Deposition reactor is simulated by Computational Fluid Dynamics (CFD) theory. By varying the way pore distributed through gas distributor, distance between inlet and gas distributor panel, form and angle of inlet, and gas pressure, the corresponding gas velocity, flow filed in the rector is calculated. The geometric structure and inflow pattern of a PECVD reactor is improved in order to provide steady and uniform flow field and improve the quality of thin films. The results show that the gas distributor panel with gradual diameter pore make the airflow more uniform, and the simulation results indicated that the distance between inlet and panel is 4.5 showed very goodeffects; The inlet trumpet-shaped structure only suits the situation that airflow speed is big; The airflow fluctuations are small when pressure is 133pa. The gas distributor is manufactured and improved the gas distribution in the real equipment.2. A three-dimensional numerical model, account for the description of fluid, thermal and chemical phenomena, has been developed for the hydrogenated amorphous silicon deposition from SiH4-H2 in a PECVD reactor. This model provides the capability to predict the main composition and deposition rates across the substrate surface. And orthogonal experimental method was applied to numerical simulation experiment for processing parameters of thin film grown by PECVD. The priority order of processing parameters affecting deposition rate is found. By means of the experimental verification, the simulation results well coincide with experimental results. All those provide theoretical basis for reasonably determining processing parameters of PECVD, deeper understanding and the optimizations of processing parameters of thin film deposition by PECVD. The results abtained through the simulation indicate: regarding the different stream velocity, the air current is bigger, the temperature field is more non-uniform, therefore to obtain the even thin film, the small inlet airflow should be used as far as possible; the conclusion through the simulation orthogonal experiment shows that the temperatur have the greatest effect on the depositon rate, next is the inlet airflow capacity, finally is H2 and the SiH4 ratio.3. This thesis analyzes the basic character of plasma and the influence of thin film growth, and simulates the distribution of RF electric field on this basis. The main research object is the relationship between deposition rate of the thin film and the RF power in deposition, showing electromagnetic field distribution under different circumstances of the space between the electrodes. By using electric field - Plasma - electrochemical reaction coupled solution method, the simulation machining technology process and equipment is carried out, in control of physical parameters in the equipment to optimizate the process and improve the performance of the equipment. The result showed that the space between the electrodes has influence on the electric-field strength and the electric potential, the distance between the electrodes is nearer, the electric-field intensity is bigger, the scalar value of electric potential is also bigger. The grounding method of electrodes also has the influence on the electric-field intensity and the electric potential. The paramaters of airflow rate, power, temperature, pressure, the silicon hydrogen variations is only have influential on the deposition rate, have not affected to the electric field and the electric potential. The airflow rate is bigger, the deposition rate is higher, but the airflow rate further increases, the deposition rate decreased. When the power is 40W, electrode spacing 25mm, the thin film uniformity is good, the deposition rate is also high.4. Flat-type of PECVD deposition equipment used to conduct tests of amorphous silicon thin film growth, then tests the thickness of the thin films by using the variable angle spectral ellipsometry and calculated deposition rate, compared with the simulation results verify the simulation model accuracy and validity of the simulation results. The result comparison between the numerical simulation and experiment shows that: the error of deposition rate between experimental value and the simulation value is lower than±7.5%, and is lower than±15% with the multi-physical field simulation value's. It is known that the two results coincide with each other well, which certifies the feasibility and validity of the model, and the model meets the needs of engineering practicesBy the study of this paper, the processing parameters of high-quality thin film material are acquired under a certain conditions. The study is of important meaning for improving the efficiency and quality of solar cell.
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