Fracture of Directionally Solidified Multicrystalline Silicon

Fracture toughness data is given for multicrystalline silicon which has been prepared by directional solidification. Results indicated a K_IC of 0.8 to 0.87 MN /m^3/2, which is consistent with data for single-crystal silicon.     

Oxygen and Carbon Distribution in 80Kg Multicrystalline Silicon Ingot

Silicon - Multicrystalline silicon (mc-Si) wafers produced by directional solidification still dominate the world market, due to the factor quality/price. The performance of solar cell depends...     

Improving the Efficiency of Multicrystalline Silicon by Adding an ARC Layer in the Front Device

High efficiency multicrystalline solar cells must improve performance while replacing higher cost monocrystalline silicon with lower cost multicrystalline silicon. Composite silicon dioxide-titanium dioxide (SiO₂?TiO₂) films are deposited on a large area of 15.6×15.6 cm² textured multicrystalline silicon solar cells to increase the incident light trapped within the device. This is being achieved through new cell device structures that improve light trapping and energy conversion capability. These new structures depend on passivated thick and thin layers of silicon dioxide and titanum dioxide grown via wet and dry thermal oxidation. By replacing dry oxidation with wet oxidation the temperatures process can be lowered from 1050^°C to 850^°C to reduce both cycle time and wafer damage.     

Effect of Additives on Making Texture Surface on Multicrystalline Silicon Wafer by Diamond Wire Sawing

Silicon - In the production of multicrystalline silicon solar cell, diamond wire sawing method (DWS) is an important technique, which has already completely replaced multiwire slurry sawing (MWSS)...     

Effect of the Silicon Nitride Coating of Quartz Crucible on Impurity Distribution in Ingot‐Cast Multicrystalline Silicon

Multicrystalline silicon ingots were fabricated via the directional solidification method in a vacuum induction furnace using silicon nitride (Si₃N₄) as quartz crucible coating. The effect of Si₃N₄ coating on the impurity content, transference, and distribution in Si ingots was investigated. The results can be summarized as follows: The impurities contained in Si ingots, including Fe, Ca, Mn, Cu, P, and B, were found to decrease at varying degrees when the inner surface of the quartz crucible was coated with Si₃N₄. A mixed layer composted by Si₃N₄ and Si was observed on the surface of the Si ingot. This mixed layer provided microdefects for the nucleation of metallic impurities. The Fe and N contents in the Si/Si₃N₄ mixed layer changed with the same tendency, and FeSi₂ particles formed on the Si/Si₃N₄ crystalline boundary. Both Fe and Ca precipitated in the SiC particles near the Si ingot/Si₃N₄‐coating interface.     

Effect of High Temperature Annealing on Crystal Structure and Electrical Properties of Multicrystalline Silicon by the Metallurgical Method

The defects of dislocations and grain boundaries (GBs) could significantly reduce the electrical properties of multicrystalline silicon (mc-Si) solar cells     

磷矿伴生硅资源制备单质硅的探讨

综述了国内外以四氟化硅、氟硅酸钠（钾）、无定SiO2为硅源制备单质硅的主要方法,并对以无定SiO2为硅源制备单质硅的工艺条件进行了研究与探索。     

Influence of Argon Gas Flow Rate on Oxygen and Carbon Impurities Concentration in Multicrystalline Silicon Grown by Directional Solidification Furnace: Numerical and Experimental Investigation

Silicon - The quality of the multi-crystalline silicon ingot mainly depends on the defects and impurity distribution. The impurities originate from the various furnace parts and feedstock. The...     

Oxidation of Chemically-Vapor-Deposited Silicon Nitride and Slnglem-Crystal Silicon

Oxidation of {111} single-crystal silicon and dense, chemically-vapor-deposited silicon nitride was done in clean silica tubes at temperatures of 1000° to woo°C. The oxidation rates of silicon nitride under various atmospheres (dry O₂, wet O₂, wet inert gas, and steam) were several orders of magnitude slower than those of silicon under the identical conditions. The activation energy for the oxidation of silicon nitride decreased from 330 to 259 kJ/mol in going from dry O₂ to steam while that for Si decreased from 120 to 94 kJ/mol. The parabolic rate constant for Si increased linearly as the water vapor pressure increased. However, the parabolic rate constant for silicon nitride showed nonlinear dependency on the water vapor pressure in the presence of oxygen. The oxidation kinetics of silicon nitride is explained by the formation of nitrogen compounds (NO and NH₃) at the reaction interface and the counterpermeation of these reaction products.     

工业硅的测定分析函待完善

研究的目的是完善工业硅检测方法,分析工业硅中的杂质来源和现有的工业硅检测方法,本次实验重点研究工业硅中杂质碳的检测方法,提出有必要修改现在的工业硅化学分析方法国家标准。     

Studies on Gold/Porous Silicon/Crystalline Silicon Junctions

Electrical transport in Gold/porous silicon/crystalline silicon junctions has been studied. The junctions are found to improve when the porous silicon is exposed to a hydrogen plasma before depositing the top metal. The hydrogen passivated junctions exhibited higher current levels and emitted light at lower voltages as compared to the unhydrogenated ones. Internal photoemission measurements were carried out to investigate the gold/porous silicon barrier. The barrier height determined from the Fowler plot is independent of the top material. The temperature dependence of the barrier height is similar to that of the crystalline silicon energy gap.     

Nonaqueous Processing of Silicon for Reaction-Bonded Silicon Nitride

Ethanolic silicon suspensions, with and without a polyethoxylated amine of low molecular weight, were studied by rheological, adsorption, electrophoretic, and sedimentation methods. Pellets were pressure-cast and nitrided to form reaction-bonded silicon nitride. Density and binding strength in the green state relate well to rheological behavior and other collodial aspects of the suspensions used, particularly the additive's role and distribution. Density and degree of nitridation in the final state are not importantly affected by the additive's use. Its greatest benefit is to modify the binding strength in the green state. The mode by which this small molecule affects the processing of silicon consists of adsorption, combined with an increased electrostatic interparticle repulsion which increases the suspension viscosity and that of undried pellets. Although the improved binding strength is accompanied by decreased green and nitrided densities, high degrees of conversion to silicon nitride are still achieved.     

A Model for Silicon Self-Diffusion in Silicon Carbide: Anti-Site Defect Motion

A simple defect interaction model was developed that explains the identical activation energies observed for carbon and silicon diffusion in single-crystal silicon carbide. In accord with experimental measurement of nonstoichiometry, the model requires a substantial concentration of silicon anti-site defects. The diffusion of silicon is limited by the motion of these defects; this is suggested to occur by their interaction with carbon vacancies. The model predicts that boron doping will increase both carbon and silicon diffusion coefficients.     

Specifics of Silicon Nitration

The sequence of formation of silicon nitride phases inside the volume of an initial silicon grain heated in a gaseous nitrogen medium is studied. Technologies for making ceramics articles based on silicon nitride are proposed.     

硅油剂及其硅污染

在生产PAN原丝过程中,干燥致密化之前要上油剂,使每根单丝表面形成油膜,防止单丝之间粘连和并丝等。目前,油剂种类主要是硅油剂。但是,硅油剂会带来硅污染,使碳纤维性能下降,这是上硅系油剂的负面影响。如何防止硅污染已提到议事日程,值得关注。本文就硅系油剂及其硅污染做一概述,以引起同仁们的重视。     

Mechanical Properties of Silicon Nanowires

Nanowires have been taken much attention as a nanoscale building block, which can perform the excellent mechanical function as an electromechanical device. Here, we have performed atomic force microscope (AFM)-based nanoindentation experiments of silicon nanowires in order to investigate the mechanical properties of silicon nanowires. It is shown that stiffness of nanowires is well described by Hertz theory and that elastic modulus of silicon nanowires with various diameters from ~100 to ~600 nm is close to that of bulk silicon. This implies that the elastic modulus of silicon nanowires is independent of their diameters if the diameter is larger than 100 nm. This supports that finite size effect (due to surface effect) does not play a role on elastic behavior of silicon nanowires with diameter of >100 nm.     

用硅藻土制取四氯化硅

论述了硅藻土制取四氯化硅的研制新过程及活性机理分析。     

二羟基硅酞菁合成方法的研究

对二氯硅酞菁的合成进行了研究,并采用甲醇析出法分离出生成的二氯硅酞菁。利用二氯硅酞菁硫酸溶液冰水析出法将二氯硅酞菁转化为二羟基硅酞菁,收率达到77%,比文献的醇解法收率有较大提高,并通过红外分析对两种化合物的结构进行了确认。     

利用双液浮选法回收硅片切割废料中SiC的试验研究

研究了以煤油作为捕收剂和载体回收硅片切割废料中碳化硅的双液浮选工艺.研究捕收剂用量、pH值、固液比及粒度对回收碳化硅纯度的影响.通过单因素及正交试验,综合考虑极差分析和方差分析的结果,确定最优工艺条件为:捕收剂用量50mL·g-1、pH值为8.3、固液比为3∶400g·mL-1、粒度8.636μm,此条件下回收的碳化硅纯度达到99.08％.采用双液浮选工艺回收太阳能硅片切割废料中的碳化硅粉体具有显著的经济效益和社会效益.     

Oxidation of Silicon, Silicon Carbide, and Silicon Nitride in Gases Containing Oxygen and Chlorine

Chlorine contamination accelerates the oxidation of silicon-based ceramics through the formation of volatile silicon chloride or silicon oxychloride species which degrade the protective character of the SiO₂ film. Accelerated attack may occur by active corrosion or formation of bubbles in the oxide layer. Si₃N₄ is much more resistant to this attack than either silicon or SiC. This resistance may be related to the presence of a thin silicon oxynitride layer below the SiO₂ scale which forms on Si₃N₄.