硅和四氯化硅耦合加氢反应体系的热力学分析

基于Gibbs自由能最小原理,对硅和四氯化硅（SiCl₄,STC）耦合加氢反应体系进行了热力学分析。通过化学平衡产物组成分布的分析,确定了反应体系主要产物为三氯硅烷（HSiCl₃,TCS）、二氯硅烷（H₂SiCl₂,DCS）、盐酸（HCl）,并构造了3个相应的独立反应,讨论了对应的反应热（ΔrHθm）、自由能（ΔrGθm）和平衡常数（Kθp）与温度的关系。计算所采用的温度为673~923 K,压力为101.325 ~2 026.5 kPa,原料H₂与SiCl₄物质的量比为1~5。结果表明,生成TCS和DCS的反应为体系随着温度升高,四氯化硅平衡转化率及三氯硅烷产率降低;高压和适中的原料配比（H₂与SiCl₄物质的量比）有利于四氯化硅转化率及三氯硅烷产率的提高。     

新型蒸发器在光纤预制棒生产中的应用

介绍了光纤预制棒的生产工艺以及国内SiCl4蒸发输送系统的技术现状。描述了新型SMR蒸发器的结构特点、技术规格和在SiCl4流量控制方面的优良性能。     

SiCl4/H2辉光放电等离子体中电子特性的在线检测

SiCl4/H2混合气体被公认为低温沉积纳米晶以及多晶硅薄膜最具潜力的气源之一.首次利用加热可调谐Langmuir探针对等离子体增强化学气相沉积系统中的SiCl4/H2放电等离子体的电子浓度和电子平均能量进行了在线检测,并分析了电子特性随系统各参数:气体压强、射频功率及氢稀释度RH的变化规律.实验结果表明:随着气体压强的升高,电子浓度不断增大而电子平均能量不断减小;增大射频功率或减小氢稀释度RH,电子浓度和电子平均能量都相应增大.此外,并对实验结果进行了定性或半定量分析.本研究工作将有助于更好地理解SiCl4/H2放电机理,改善并优化沉积优质多晶硅薄膜的工艺参数.     

SiCI4/H3PO4添加的PVDF复合电解质膜的研制

以聚偏氟乙烯(PVDF)为基质,加入适量的H3PO4和SiCl4,利用流延法制备了H3PO4/SiCl4掺杂的PVDF质子导电膜,采用交流阻抗谱法研究了质量分数为0.15H3PO4和不同质量分数SiCl4的PVDF电解质膜的导电性能及相对湿度对电导率的影响.结果表明,质量分数为0.10SiCL4,0.15H3PO4的PVDF复合电解质膜,室温电导率为6.37×10-2 S/cm,相对湿度在20%～80%范围内,电解质的电导率变化不大.     

Integrated UV-based photo microreactor-distillation technology toward process intensification of continuous ultra-high-purity electronic-grade silicon tetrachloride manufacture

Ultra-high-purity silicon tetrachloride (SiCl₄) is demanded as an electronic-grade chemical to meet the stringent requirements of the rapidly developing semiconductor industry. The high requirement for ultra-high-purity SiCl₄ has created the need for a high-efficient process for reducing energy consumption as well as satisfying product quality. In this paper, a mass of production technology of ultra-high-purity SiCl₄ was successfully developed through chlorination reaction in the ultraviolet (UV)-based photo microreactor coupled with the distillation process. The influences of key operational parameters, including temperature, pressure, UV wavelength and light intensity on the product quality, especially for hydrogen-containing impurities, were quantified by the infrared transmittance of Fourier transform infrared spectroscopy (FT-IR) at 2185 cm⁻¹ and 2160 cm⁻¹ indicating that characteristic vibrational modes of SiH bonds, as well as the operating conditions of distillation were also investigated as key factors for metal impurities removing. The advanced intensification of SiCl₄ manufactured by the integration of photo microreactor and distillation achieves the products with superior specifications higher than the standard commercial products.     

用SiCl_4/O_2-PECVD技术低温沉积Si基厚SiO_2薄膜

选取不含 H2 的 Si Cl4 / O2 混合气体作为反应源气体 ,并利用普通的 PECVD技术来实现低温沉积 Si基微米厚度的 Si O2 薄膜 ,测试并分析薄膜的红外吸收谱以及工艺参数对沉积过程的影响。     

SiCl_4、PPh_3促进的TiCl_4/Ni(acac)_2复合催化剂的乙烯聚合研究

制备了SiCl4、PPh3促进的MgCl2 -SiO2 -ZnCl2 为载体 ,TiCl4/Ni(acac) 2 为主催化剂的A、B型乙烯聚合高效催化剂。研究了SiCl4、PPh3对乙烯气相聚合的影响 ,发现SiCl4能大幅度提高催化效率 ,PPh3使催化效率出现峰值。用DSC、IR、1 3CNMR对聚合产物进行结构性能的分析和表征。结果表明 ,TiCl4/Ni(acac) 2 组成的复合催化剂较单一Ti系催化剂的聚合产物熔点、结晶度、密度、相对分子质量明显降低。添加PPh3的B型催化剂获得了支化度为 3～ 5的支化聚乙烯 ,表明B型催化剂具有一定的低聚和原位共聚功能。     

用PECVD技术低温低氢稀释快速生长纳米晶硅薄膜的研究

以SiCl4和H2为气源,用等离子体增强化学气相沉积技术,在300℃的低温下,研究不同的氢流量对纳米晶硅薄膜生长特性的影响.实验发现,氢对薄膜生长特性的影响有异于SiH4/H2,在一定功率下,薄膜的晶化率随氢流量的减小而增加;而薄膜的生长速率也强烈依赖于氢流量,随氢流量的减小而增大,与氢流量对薄膜晶化度的变化关系一致.通过调控氢流量,在低氢流量条件下获得了生长速率高达0.35nm/s,晶化度高达76%的晶化硅薄膜.     

SiCl4氢化转化为SiHCl3过程的热力学

应用有关热力学数据研究了与多晶硅主要生产工艺即西门子法相关的“Si-Cl-H”三元系的复杂化学反应,研究SiCl4氢化转化为SiHCl3过程中可能发生的15个反应,给出15个反应的ΔGθm -T图;并确定5个独立的反应,给出这5个独立反应的KθP -T图;高温时主反应(1)的Kp增长较慢,而反应(2)和(5)的KθP快速增大,1 373K时,主反应(1)的KθP较小,为0.157 1.进一步研究温度、压强和进料配比nH2/nsicl4对SiCl4氢化率的影响,并绘制出SiCl4氢化率随这些因素的变化曲线.结果表明:当压强和进料配比一定时,SiCl4的氢化率随温度的升高先增加后降低;增大压强或增加进料配比nH2/nsiCl4都会提高SiCl4的氢化率;SiCl4氢化转化为SiHCl3过程的最佳操作条件为温度为1 000℃,压强为0.3 MPa,进料配比nH,/nSiCl4为4,在此条件下,SiCl4的氢化率为25.78％.     

Thermodynamic behaviors of SiCl2 in silicon deposition by gas phase zinc reduction of silicon tetrachloride☆

The modified Siemens process, which is the major process of producing polycrystal ine silicon through current technologies, is a high temperature, slow, semi-batch process and the product is expensive primarily due to the large energy consumption. Therefore, the zinc reduction process, which can produce solar-grade silicon in a cost effective manner, should be redeveloped for these conditions. The SiCl2 generation ratio, which stands for the degree of the side reactions, can be decomposed to SiCl4 and ZnCl2 in gas phase zinc atmosphere in the exit where the temperature is very low. Therefore, the lower SiCl2 generation ratio is profitable with lower power consumption. Based on the thermodynamic data for the related pure substances, the relations of the SiCl2 generation ratio and pressure, temperature and the feed molar ratio nZn=nSiCl4 ? ? are investigated and the graphs thereof are plotted. And the diagrams of KpΘ–T at standard atmosphere pressure have been plotted to account for the influence of temperature on the SiCl2 generation ratio. Furthermore, the diagram of KpΘ–T at dif-ferent pressures have also been plotted to give an interpretation of the influence of pressure on the SiCl2 gener-ation ratio. The results show that SiCl2 generation ratio increases with increasing temperature, and the higher pressure and excess gas phase zinc can restrict SiCl2 generation ratio. Finally, suitable operational conditions in the practical process of polycrystalline silicon manufacture by gas phase zinc reduction of SiCl4 have been established with 1200 K, 0.2 MPa and the feed molar ratio nZn=nSiCl4 ? ? of 4 at the entrance. Under these conditions, SiCl2 generation ratio is very low, which indicates that the side reactions can be restricted and the energy consumption is reasonable.