在国产炉上研制区熔Φ101mm硅单晶

高反压、大电流电力电子器件的发展要求区熔硅单晶直径进一步增大.大直径区熔硅单晶的拉制最大困难在于高频加热设备能力和成晶工艺条件.目前国内生产φ101mm.区熔硅单晶只有一个厂家能在进口设备上实现.我们通过设备技术改造和工艺条件摸索,成功实现了在国产设备上拉制φ101mm.区熔硅单晶.填补了空白,节约了外汇,打破了迷信,为国内硅材料生产厂家和国产设备制造厂树立了信心.     

历产炉上研制区熔Φ101mm硅单晶

高反压、大电流电力电子器件的发展要求区熔硅单晶直径进一步增大。大直径区熔硅单晶的拉制最大困难在于高频加热设备能力和成晶工艺条件。目前国内生产Φ１０１ｍｍ区熔硅单晶只有一个厂家能在进口设备上实现。我们通过设备技术改造和工艺条件摸索，成功实现了在国产设备上搠制Φ１０１ｍｍ区熔硅单晶。填补了空白，节约了外汇，打破了迷信，为国内硅材料生产厂家和国产设备制造厂树立了信心。     

Φ105 mm区熔硅单晶的生长工艺研究

介绍了FZ硅单晶的熔区悬浮原理 ,说明了生产Φ10 5mmFZ硅单晶所用多晶原材料的技术标准 ,通过对不同形式的加热线圈进行分析 ,指出了较理想的加热线圈 ,讨论了反射器和改进后的晶体夹持装置的具体应用。对Φ10 5mmFZ硅单晶的关键生长工艺进行了描述     

纯氩气氛下生长直径70毫米区熔硅单晶的工艺

本文概述了拉制大直径区熔硅单晶的试验工作,着重介绍硅单晶的生长设备、氩气净化、加热线圈、操作参数、等诸方面的工艺技术条件。     

科技简讯

我国第一台直拉大直径硅单晶炉诞生大直径硅单晶是发展大觇模集成电略的关键材科,用大直径硅单晶切制硅片可以提高生产率和材科利用率,从而降低成本。为把我国硅单晶材料的生产提高到一个新的水平,上海有色金属研究所自行设计、自行制造了一台高达6.5米的大直径硅单晶炉,为拉制大直径硅单晶准备了条件。经调试和投料11公斤试拉表明,各项性能均达到预定的指际:投料量可达16公斤以上,真空度达10~(-5)乇,温度控制情度达±0.5℃,可用于高真空、低真尘、充氩或     

微型计算机自动控制CZ硅单晶等径生长

采用CZ法生长硅单晶时,其固体和熔体中的温度梯度是决定晶体生长速度的主要因素。生长速度、晶体直径和炉温三者之间存在着复杂的联系,晶体直径的控制又是一个大热容量滞后的多变量系统。因此常规仪表难以胜任。上海有色金属研究所在国产TDR-40炉上采用微型计算机自动控制晶体等径生长,减轻了劳动强度和减少了操作失误,有效地保证硅单晶质量和实得率。控制用微型计算机以Cromemco CSⅡ为     

大直径p型探测器级硅单晶的研制

为了满足对大直径Ｐ型探测器级硅单晶的需求，在原有小直径单晶工艺的基础上，采用线圈喷砂打毛、甩尾、保温提纯、快速成晶等技术，成功地拉制出Φ５０、Φ６２和Φ７５的Ｐ型高阻硅单晶。用本区熔工艺拉制的单晶可做到无位错、无漩涡缺陷。对技术中涉及的有关机理进行了初步探讨。     

DL—78型单晶炉的热场和减压工艺

本文论述了硅单晶生长炉从1公斤级增长到15公斤级时，其热场设计的基本方法及大容量、长时间拉晶过程中采用的减压工艺。指出在随器件要求而增加硅片直径时，硅单晶锭的直径和长度应成比例增加，即硅单晶长度：直径应大于10:1，而在晶体生长中，坩埚直径。晶体直径应大于2．5：1。在大容量、长时间的晶体生长条件下，保持2．7×103Pa左右的炉压、一定的氩气流量和合理的氩气导流结构是避克拉晶过程中SiO在空间凝聚或在炉内物件表面沉积的必要条件．     

Φ20mm硅单晶的生长工艺特点

在全自动拉晶条件下，讨论了拉制Φ２００ｍｍ硅单晶遇到的新问题。热场配置、工艺参数的选择、石英坩埚泊选用等有了更严格的要求。合理的轴向温度梯度和径向温度梯度、低拉速、低晶转瘃规范的拉晶工艺是拉制大直径单晶的关键。     

Φ200 mm硅单晶的生长工艺特点

在全自动拉晶条件下，讨论了拉制Φ２００ｍｍ硅单晶遇到的新问题。热场配置、工艺参数的选择、石英坩埚的选用等有了更严格的要求。合理的轴向温度梯度和径向温度梯度、低拉速、低晶转及规范的拉晶工艺是拉制大直径单晶的关键。     

VGF法生长6英寸Ge单晶中热应力的数值模拟优化

VGF技术生长单晶时温度梯度较低,生长速率较小,目前已成为生长大直径、低位错密度晶体的主流技术之一。采用数值模拟研究了VGF法6英寸低位错Ge单晶的生长,结果表明在采用自主研发的VGF炉生长6英寸Ge单晶时,晶体生长过程中晶体与熔体中均具有较低的温度梯度(这里的温度梯度是指的界面附近的温度梯度),尤其当晶体生长进入等径生长阶段后,晶体中的轴向温度梯度在2～3 K.cm-1之间,熔体中的轴向温度梯度0.8～1.0 K.cm-1之间;晶体中的热应力除边缘外均在(2～9)×104 Pa之间,低于Ge单晶的临剪切应力,且晶体生长界面较平整;坩埚与坩埚托之间的间隙对于晶体生长中的边界效应影响显著,将8 mm间隙减小至2 mm后,埚壁外侧的径向热流增加,使得晶体边缘的最大热应力减小至0.21 MPa和Ge单晶的临剪切应力相当,实现了热场的优化。     

In-Situ Observation of SiC Bulk Single Crystal Growth by XRD System

In-situ analysis for SiC bulk single crystal growth was reported using vertical X-ray diffractometer system. A furnace for SiC sublimation growth combined with the XRD system which possessed three kinds of functions including topography, rocking curve measurement and crystal growth rate monitoring was developed. These functions could contribute as a powerful tool finding the optimum growth condition by dynamic observation in the crucible. In this study, the in-situ X-ray topographs succeeded to capture dynamic elongation of defects and dislocation generated in the SiC growing crystals. The in-situ rocking curve measurement reviled appearance of mosaic structure in the SiC crystal grown with high growth rate. The in-situ growth rate monitoring also succeeded very precisely using the direct X-ray beam absorption. On the base of findings and facts obtained by the in-situ observations, the importance for the SiC growth was discussed.     

单晶型LiNi0.8Co0.1Mn0.1O2正极材料的制备及性能对比

基于高镍三元正极材料容量和成本等方面的优异性,通过熔盐法结合高温固相法进行梯度煅烧,成功制备出了具有大尺寸单晶颗粒状的高镍LiNi_0.8Co_0.1Mn_0.1O₂材料,并与传统固相反应煅烧制备的材料进行比对,通过XRD衍射分析其结构特征,反映阳离子混排程度。依托扫描电子显微镜和透射电子显微镜,表征其表面形貌和晶体特征,研究表明:在经过循环伏安测试后,在高倍率测试条件下,循环稳定性和容量保有量的优势明显,契合锂离子电池近些年在快速发展过程中所面临的安全稳定的条件。这种采用熔盐法制备的NCM-811材料为制备微米级单晶型的正极材料提供了新的思路。      

优化炼钢工艺 提高技术指标

临钢炼钢设备落后，产品结构单一，不利于临钢发展。通过近几年优化炼钢工艺，使各项经济技术指标大幅度提高。     

钨的冶金及其加工技术

简要综述了钨的冶金和加工技术。除了用于制备高纯金属以及单晶等场合之外,钨及其合金的制备仍以粉末冶金方法为主,但近些年来在纳米钨粉的制备、掺杂钨合金的研究、钨合金的注射成形和复合材料的制备方面有很快地发展。     

冷拔连续铸造单晶和多晶铜线材的退火行为

采用光学金相以及电子背散射衍射技术,对单晶连续铸造以及传统连续铸造2种技术制备的单晶和多晶铜线材冷拔变形组织的再结晶温度、完全再结晶后的晶粒尺寸以及再结晶组织的孪晶界等进行分析,并比较两者之间的差异.研究结果表明,与多晶铜线材相比,单晶铜线材的再结晶温度较高,完全再结晶的晶粒尺寸较大;随变形量的增加,两者之间的再结晶温...     

An experimental study on process variables in crystal growth by ohno continuous casting

Crystal growth, by the recently developed Ohno continuous casting (O.C.C) process, was studied using pure tin. The effects of four process variables on crystal growth were studied: these were the mold exit temperature, the casting speed, the melt temperature, and the cooling condition. Small single crystals of 6.4 mm diameter were produced both by repeated necking and by using single crystal seeds. Excellent surface quality was obtained in these small-diameter crystals.     

Mortality attributed to respiratory problems among finisher pigs in the United States

Over a 6-month period, the mean mortality risk (based on 393 operations participating in the United States National Animal Health Monitoring System 1995 National Swine Study, and representing operations with > or = 300 market hogs in 16 states), was 2.3 +/- 0.2% in the grower/finisher production phase (where figures after the +/- represent the standard error of the estimate). Mortality > or = 4% was experienced by 13.5 +/- 2.9% of grower/finisher operations, while 63.6 +/- 5.3% had < or = 2% mortality. To identify factors associated with > or = 4% mortality, stepwise logistic regression [Statistical Analysis Systems, 1989. SAS/STAT User's Guide, Version 6, 4th edn, Vol. 2. SAS Institute, Cary, NC, 794 pp.] was performed twice: once using operations with all mortality rates, and again excluding operations with between 2% and 4% mortality. Final models were run with SUDAAN [Shah, B.V., Barnwell, B.G., Bieler, G.S., 1996. SUDAAN User's Manual, Version 6.40, 2nd edn. Research Triangle Institute, Research Triangle Park, NC, 492 pp.] to take the sample design into account. In addition, SAS and SUDAAN logistic regression models were developed to analyze factors associated with > 2.3% mortality among grower/finisher pigs. Mean weaning age < or = 28 days entered all models as being associated with increased mortality in the grower/finisher unit. Not obtaining all grower/finisher pigs from farrowing units belonging to the operation was associated with > or = 4% mortality among grower/finisher swine. Not typically giving grower/finisher pigs antibiotics or other agents as disease-preventives or growth-promotants in the feed or water, and ranking producer organizations as very or extremely important sources of antibiotic information were associated with < or = 2.3% mortality in the grower/finisher phase.     

难熔金属单晶技术现状与展望

综述了当前难熔金属单晶制备的技术现状，介绍了难熔金属单晶技术进展，并对难熔金属合金单晶前景进行了展望。作者认为难熔金属单晶制备技术应沿着如下几个方面发展：进一步降低杂质元素特别是C元素的含量，提高单晶纯度水平；发展大规格、多品种的难熔金属单晶产品；进一步提高难熔金属合金单晶耐热性能和使用温度，研发出新的难熔金属合金单晶制备技术。