流化床化学气相沉积多晶硅的技术进步与挑战

Various methods for production of polysilicon have been proposed for lowering the production cost and energy consumption, and enhancing productivity, which are critical for industrial applications. The fluidized bed chemical vapor deposition (FBCVD) method is a most promising alternative to conventional ones, but the homogeneous reaction of silane in FBCVD results in unwanted formation of fines, which will affect the product quality and output. There are some other problems, such as heating degeneration due to undesired polysilicon deposition on the walls of the reactor and the heater. This article mainly reviews the technological develop-ment on FBCVD of polycrystalline silicon and the research status for solving the above problems. It also identifies a number of chal-lenges to tackle and principles should be followed in the design of a FBCVD reactor.     

用于多晶硅生产的流化床反应器设计进展

流化床法多晶硅制造工艺能够大幅降低多晶硅制造成本,对光伏发电实现平价上网的最终目标具有重要意义。该文概述了流化床反应器结构和工艺设计中需要解决的关键问题,以及以往的一些成功案例,指明了今后的发展方向。     

流化床法制备粒状多晶硅研究进展

综述流化床法制备粒状多晶硅的技术概况及生产技术问题的研究情况。     

化学气相沉积法多晶硅生产工艺的研究

对化学气相沉积法生产多晶硅的工艺进行了研究。多晶硅生产过程中的温度、流量、压力、物料摩尔比、进料气体分布以及操作安全性是影响多晶硅生产的重要因素,通过生产过程的研究和总结,实现了相关参数控制和安全性的优化,为企业带来了可观效益。     

太阳能级多晶硅生产技术研究现状及展望

论述了目前太阳能级多晶硅的主要生产技术研究现状,并对一些具有代表性的新工艺进行介绍.太阳能级多晶硅的生产方法主要包括改良西门子法、硅烷法、流化床法、冶金法及锌还原法.指出硅烷法和流化床法是未来多晶硅生产技术发展的趋势和方向,冶金法和锌还原法的工艺尚不够成熟,但具有潜力.     

多晶硅化学气相沉积数值模拟的研究进展

介绍了多晶硅气相沉积反应的几何模型和数学模型。回顾了。重点综述了近几年国内外还原炉内SHC13-H系统三维过程数值模拟的研究进展,并对其评述。讨论了化学气相沉积数值模拟的研究现状和存在的问题,展望了今后的发展方向。     

硅烷流化床制备粒状多晶硅的研究进展

硅烷流化床生产粒状多晶硅的技术具有节能、高效、环境友好等优点,是生产太阳能级多晶硅的首选工艺技术,但国内对于该工艺技术的研究仍处于起步阶段。本文简介了硅烷流化床的基本原理,包括操作原理和反应模型,并讨论了温度、硅烷分压、颗粒尺寸以及流化速度等反应条件对硅烷流化床内流动稳定性和硅粉尘产生的影响。根据发展硅烷流化床所面临的热壁沉积、产生硅粉尘、加热方式的选择、硅晶种的获得、气体分布方式的控制以及产品纯度的控制等技术挑战,分析了不同的流化床设计对这些技术挑战的解决方案,指出了不同的流化床设计的优缺点与工业应用前景。讨论了硅烷流化床的CFD模拟与一般的流态化模拟的区别,并回顾了相关的研究工作。最后指明了对硅烷流化床技术的研究应从优化反应条件、改善反应器设计以及完善多尺度模拟硅烷流化床的模型三个方面着手。     

硅烷法制备多晶硅工艺的热力学分析

根据吉布斯自由能理论,对硅烷法制备多晶硅工艺进行了热力学分析,研究了化学气相沉积过程中温度对硅棒生长速度、物理特性及单位能耗的影响,为硅烷法制备多晶硅工艺参数的调整提供了科学依据.     

硅粉密相气力输送技术在多晶硅生产中的应用

介绍某多晶硅厂对硅粉加料采用密相气力输送技术的输送方式和工艺流程,分析了该气力输送系统中主要设备和管道、阀门选型及设计时的考虑因素。     

流化床技术制备粒状多晶硅的研究进展

概述流化床技术制备粒状多晶硅的研究进展,简介粒状多晶硅的生长机制和物理性能,阐述流化床技术在多晶硅生产领域的发展方向。     

纳米聚团床制备碳纳米管的生长机理

采用催化化学气相沉积法(CCVD)，在550~750℃温度范围内，于内径44 mm、高1000 mm的石英管纳米聚团床中制备了碳纳米管；通过SEM, TEM, TGA等多种分析手段对碳纳米管产品的形貌和质量进行了分析；把相同条件下的纳米聚团床法与前人固定催化剂法的结果进行了比较，并考察了纳米聚团床中反应条件对碳纳米管生长的影响；通过对电镜照片和反应转化率动态数据的深入分析，对纳米聚团床中碳纳米管生长机理的特殊性进行了初步探讨.     

Preparation of Fine Grained SiC Layer by Fluidized Bed Chemical Vapor Deposition with Pulsed Propylene

A novel strategy named pulsed propylene method was developed to prepare fine grained SiC layer. The SiC layer was uniformly coated on ceramic microspheres by fluidized bed chemical vapor deposition. Propylene was introduced into the deposition system in pulsed form at proper time intervals. By adjusting the propylene concentration and the pulse interval, the grain size of SiC can be controlled from micrometer scale to nanometer scale and the microstructure of the SiC layer changed from large columnar grains to fine equiaxed grains. The SiC layer with average grain size less than 300 nm was obtained with the pulsed propylene under a volume concentration of 5% at an injection time interval of 2 min. The as‐prepared fine grained SiC layer exhibited higher hardness and higher oxidation resistance than that of columnar grained SiC.     

Manufacture of Granular Polysilicon from Trichlorosilane in a Fluidized‐Bed Reactor

Manufacturing of polysilicon by chemical vapor deposition from SiHCl₃ in a fluidized‐bed reactor was studied. The effects of reaction temperature, H₂/SiHCl₃ ratio, gas velocity, and seed particle loading were evaluated. The outlet gas composition was analyzed by gas chromatography. The physical features of the product particles were determined by scanning electron microscopy and laser particle size analyzer. Well‐grown product particles were obtained. The temperature and H₂/SiHCl₃ ratio significantly affected conversion, yield, and selectivity, which were less affected by gas velocity and seed particle loading at higher temperatures. The surface reaction kinetics determined the product yield only at lower temperatures, and thermodynamic equilibrium was approached at temperatures above 900 °C.     

流化床法制备硅化镁的工艺研究

在一定的温度,高纯氢气氛围下,以硅粉、镁粉为原料,于流化床反应器中制备硅化镁.考察了硅粉与镁粉粒度、反应温度、反应时间、不同原料配比以及载气流量对反应的影响.实验结果表明,实验最佳条件是镁粉与硅粉摩尔比为2.05∶1、镁粉和硅粉的粒度在100～160目且粒度相差20目以内、反应温度570℃、反应时间2.0h、载气流量为3.0～5.0 L/min.在此实验条件下,硅化镁的质量含量≥98.3％.     

Optimization of Reaction Conditions in a Fluidized‐Bed for Silane Pyrolysis

The fluidized‐bed chemical vapor deposition (CVD) process for polycrystalline silicon production is considered to be the most attractive alternative to the conventional bell‐jar process. In order to obtain stable operation, high space‐time‐yields and high purity of the product several obstacles have to be eliminated. Reaction conditions must be optimized to avoid the homogeneous decomposition of silane and minimize silicon dust formation. The effect of temperature, silane partial pressure, gas velocity and the size of bed particles has to be identified. These dependencies and the interaction between hydrodynamics and kinetics of homogeneous and heterogeneous CVD‐reactions were studied in a laboratory‐scale fluidized‐bed reactor.     

流化床干燥聚碳酸酯小试实验研究

使用流化床小试装置对聚碳酸酯粉料进行干燥,绘制聚碳酸酯干燥速率曲线,初步证明了卧式流化床干燥聚碳酸酯具有一定的可行性。     

SiHCl_3流化床制备粒状多晶硅研究进展

综述了近年来关于三氯氢硅(Si HCl3)流化床制备颗粒状多晶硅工艺技术研究状况,详细介绍了国内外关于颗粒状多晶硅制备流化床设备的设计思路及制备情况,并讨论了反应器制备方法对产品纯度的影响,分析了"热壁流化床"的技术缺陷,"冷壁流化床"的技术优势,对下一步流化床技术发展进行了展望。     

Structural study of β‐SiC(001) films on Si(001) by laser chemical vapor deposition

β‐SiC thin films have been epitaxially grown on Si(001) substrates by laser chemical vapor deposition. The epitaxial relationship was β‐SiC(001){111}//Si(001){111}, and multiple twins {111} planes were identified. The maximum deposition rate was 23.6 μm/h, which is 5‐200 times higher than that of conventional chemical vapor deposition methods. The density of twins increased with increasing β‐SiC thickness. The cross section of the films exhibited a columnar structure, containing twins at {111} planes that were tilted 15.8° to the surface of substrate. The growth mechanism of the films was discussed.     

流化床冷却系统在尿素生产中的应用

介绍了新型浅床层带特殊形式导向分布板的矩形流化床冷却系统的工艺流程、特点及其在尿素生产中的应用情况。实际运行结果表明:该流化床冷却系统操作稳定可靠,能满足颗粒尿素的冷却要求;对于扩产改造系统,可解决原造粒塔冷却能力不足的问题;对于新建系统,可降低造粒塔高度,节省投资,明显改善尿素成品的质量。