太阳电池用多晶硅及其吸杂研究现状

综述了几类主要的太阳电池用多晶硅及其吸杂研究现状.评述了当前太阳电池领域涉及到的几类多晶硅如铸造多晶硅、冶金法多晶硅、西门子法多晶硅等的优缺点.详细描述了多晶硅的吸杂类型、吸杂过程、吸杂影响因素等.给出了本课题组关于冶金法多晶硅吸杂实验的一些初步研究结果.展望了多晶硅及其吸杂技术的发展.     

3d过渡族金属杂质在硅中的行为

本文综述了３ｄ过渡族金属在直拉硅单晶中的扩散、溶解、沉淀及间隙位演变等性质，介绍了国际上在此领域的研究进展，为进一步开展这方面的工作提供了有益的借鉴。     

3d过渡族金属杂质在硅中的行为

本文综述了３ｄ过渡族金属在直拉硅单晶中的扩散，溶解，沉淀及间隙位演变等性质，介绍了国际上此领域的研究进展，为进一步开展这方面的工作提供了有益的借鉴。     

超大规模集成电路硅片的内吸杂

介绍了吸杂的分类与效果以及内吸杂工艺,并综述了金属在硅中的性质,主要阐明了乳在内吸杂中的作用,简述了氮对吸杂的影响,并讨论了内吸杂的物理机理。最后探讨了今后吸杂的发展方向。     

高温氢气退火提高硅片质量的研究

研究了硅片高温氢气退火的工艺技术,实验显示,在高温1150℃,在高纯氢气氛中退火处理至少60min,在硅片表面产生约50μm以上的洁净层。测试了退火后硅片中氧的深度分布,发现硅片表面有一层低氧区,能提高硅片的质量,使氧化层错的密度降低一个数量级,测试数据还表明高温氢退火对降低COP缺陷的密度和提高氧化层的质量也有一定的效果。     

直拉硅中氧化诱生层错研究进展

硅中的氧化诱生层错（OSF）是一种重要的工艺诱生缺陷,会对微电子器件产生重大的影响,为提高硅片质量,要求对OSF有充分了解。综述了氧化诱生层错的研究进展,着重讨论了OSF的形成动力学、影响因素和检测方法,并指出：OSF是一种由点缺陷行为决定的工艺诱生缺陷。     

造渣精炼去除多晶硅中B杂质的研究

以现有实验成果为基础,采用相关热力学及动力学分析,综述了造渣精炼去除多晶硅中B杂质的原理、影响因素及发展现状,总结了国内外已有研究结果,为进一步研究提供了理论依据。     

多晶硅扩散氧化层对太阳电池性能的影响

重点研究了多晶硅扩散氧化层对电池性能的影响,并对大规模生产多晶硅扩散工艺进行了优化研究.采用少子寿命测试仪分析了扩散前后的硅片少子寿命,发现当扩散氧化时的干氧流量控制在2800sccm,扩散后的方块电阻控制在60～70Ω/□时,扩散后硅片少子寿命最高达到了10.45μs,与扩散前的硅片少子寿命相比延长了5倍多;此时的太阳电池并联电阻和短路电流分别高达40.4Q和8522mA,光电转换效率也由16.69％(干氧流量2000sccm)提高到了16.83％.此外,主要针对扩散氧化层对片内方阻均匀性及少子寿命的影响做了解释.     

定向凝固多晶硅的结晶组织及晶体缺陷与杂质研究

多晶硅是目前最主要的光伏材料,其结晶组织、缺陷和杂质含量显著影响太阳能电池的转换效率.通过控制硅锭定向凝固过程获得取向一致、粗大均一的结晶组织和采用各种吸杂及钝化方法降低杂质及缺陷对电学性能的影响是目前提高多晶硅太阳能电池转换效率的重要途径.介绍和评述了国内外包括本研究组对多晶硅的结晶组织及控制、晶体缺陷、杂质水平与分布及其与硅片性能关系的研究进展,并对当前的各种吸杂与钝化方法及其效果进行了总结.     

多晶硅材料制备中施主杂质磷的模拟计算研究

多晶硅是主要功能半导体材料。磷作为主要施主杂质,其含量直接影响多晶硅的半导体性能。多晶硅制备普遍采用改良西门子工艺,在密闭、复杂的动态工艺系统中,磷存在的化合物、含量及转化,无法实际有效掌握、但又非常重要;利用Aspen plus等软件对流程中主要的工艺系统模拟计算,并结合热力学反应分析,研究磷的分布规律、存在形式和量化含量;研究发现磷的主要化合物类型除PCl3,在还原或氢化炉这种高温、富氢条件下,PCl3会转化成PH3。在还原过程中磷存在富集效应。尾气回收解析塔解析效果的好坏影响着磷去除效果。研究结果表明,若要使还原多晶硅产品符合国标太阳能三级磷≤7.74ppba的要求,则对本文建立的模拟工艺流程,需要精馏前、后的SiHCl3中P应分别≤2557 ppbw和1.79ppbw。     

Influence of different surface treatments on multicrystalline silicon wafers for defect characterization by LBIC

In this paper, we investigate the influence of different chemical treatments on the surface of multicrystalline Silicon (mc-Si) wafers, for both revealing grain boundaries and intra-grain defects. Electrical characterization by light beam-induced current (LBIC) was also carried out after the treatments. Several pieces of ~2 × 2 cm², from mc-Si wafers, were mechanically polished and chemically etched and subsequently metallized with gold (on both surfaces) by sputtering, using optimized deposition times for doing transparent electrodes suitable for LBIC mapping. The surface treatments are discussed in terms of their capabilities to reveal the crystal defects and to provide the best conditions for efficient LBIC signals directly on silicon substrates, in the absence of a p–n junction. The best surface treatments allowing both revealing crystallographic defects and permitting the measurement of highly contrasted LBIC maps is the KOH etching. A large number of intra-grain defects are clearly revealed, being their electrical activity sensitively higher than that of the grain boundaries.     

Some unsolved problems on Czochralski growth of silicon from the viewpoint of materials modeling

Summary In this report the oxidation-induced stacking fault ring in Czochralski-grown Si, which is not fully understood in spite of the practical importance, is discussed, as well as the necessity of materials modeling to understand it.     

Influence of high temperature processing of sol-gel derived barium titanate thin films deposited on platinum and strontium ruthenate coated silicon wafers

Thin films of barium titanate (BTO) of 200 nm thickness, derived from an alkoxide-carboxylate sol-gel process, were deposited on Pt/Ti and SrRuO₃/ZrO₂-8%Y₂O₃ coated Si wafers. Films with a dense columnar microstructure were obtained by repeated deposition of thin amorphous layers from low-concentrated sols, and crystallization at 800 °C. This method added 10 nm thickness to the crystalline BTO film in each deposition step. The harsh processing conditions had a negative impact on the platinized silicon wafers, where Pt-Si silicides were formed. This led to diffusion of Si into BTO and interfacial silicate formation. The interfacial silicate layer was the cause of deteriorated dielectric and ferroelectric properties of the BTO layer. Use of SrRuO₃/ZrO₂-8%Y₂O₃/Si substrates solved the problem. No diffusion of Si was observed, and BTO films with good dielectric and ferroelectric properties were obtained.     

CuZnAl形状记忆合金马氏体相中非基面层错的研究

利用透射电子显微镜精确地测定了ＣｕＺｎＡｌ形状记忆合金马氏体相中（１２８）１８Ｒ非基面层错的层错面为（１３７）。一种新的非基面层错被确定为（１３１）１８Ｒ，其位移矢量为１／２（１０１）。     

硅基分子筛富氧膜的研究

通过先制备大分子链结构规整的硅基聚合物先体 ,再利用热裂解法制得透气率和分离特性都较好的气体分离膜 .这种制膜技术已经基本成熟 ,制备成品率可达 80 %～ 90 % .把成品膜组装成小型膜装置后对空气进行实际分离 ,经检测发现其富氧效果显著 .例如在 0 .3MPa的压力下 ,分离率可达 4 1% ,通量达到了 18.6 2L/ (m2 ·d) .     

Mechanical properties of carbon-modified silicon oxide barrier films deposited by plasma enhanced chemical vapor deposition on polymer substrates

Cohesive and adhesive properties of silicon oxide barrier coatings deposited from an oxygen/hexamethyldisiloxane gas mixture by plasma enhanced chemical vapor deposition, with controlled incorporation of carbon on 12 μm thick polyethylene terephtalate films were investigated. The reactor was equipped with a 2.45 GHz slot antenna plasma source and a 13.56 MHz-biased substrate holder. The two plasma sources were operated separately or in a dual mode. It was found that no or negligible internal stresses were introduced in the silicon oxide coatings as long as the increase of energy experienced by the film was compensated by the densification of the oxide. For a range of process parameters and carbon content on the changes of the crack onset strain, adhesion, and cohesion were found to be similar. Generally a high crack onset strain or good adhesion and cohesion were measured for films with an increased carbon content, although this was obtained at the expense of the gas barrier performance. Promising approaches towards high-barrier thin films with good mechanical integrity are proposed, based on coatings with a gradient in the carbon content and in the mechanical properties, on nano-composite laminates, and on organo-silane treatments.     

基于经验模式分解(EMD)的齿轮箱齿轮故障诊断技术研究

简述了齿轮箱传统信号分析技术与经验模式分解(EMD)技术的异同，并详细论述了EMD的分解原理和富立叶变换的关系。针对齿轮箱振动加速度数据，运用EMD分解技术，得到IMF(Intrinsic Mode Function)模式分量，提出了基于IMF及功率谱(PSD)的IMFPSD216指标和基于IMF及滤波统计的IMFFLT指标，并验证了它们的有效性。运用这些指标正确明显地分辨出齿轮箱齿轮失效。     

Effects of argon and oxygen flow rate on water vapor barrier properties of silicon oxide coatings deposited on polyethylene terephthalate by plasma enhanced chemical vapor deposition

Plasma polymer coatings were deposited from hexamethyldisiloxane on polyethylene terephthalate (PET) substrates while varying the operating conditions, such as the Ar and O₂ flow rates, at a fixed radio frequency power of 300 W. The water vapor transmission rate (WVTR) of the untreated PET was 54.56 g/m²/day and was decreased after depositing the silicon oxide (SiO_x) coatings. The minimum WVTR, 0.47 g/m²/day, was observed at Ar and O₂ flow rates of 4 and 20 sccm, respectively, with a coating thickness of 415.44 nm. The intensity of the peaks for the Si-O-Si bending at 800-820 cm^− 1 and Si-O-Si stretching at 1000-1150 cm^− 1 varied depending on the Ar and O₂ flow rates. The contact angle of the SiO_x coated PET increased as the Ar flow rate was increased from 2 to 8 sccm at a fixed O₂ flow rate of 20 sccm. It decreased gradually as the oxygen flow rate increased from 12 to 28 sccm at a fixed Ar carrier gas flow rate. The examination by atomic force microscopy revealed a correlation of the SiO_x morphology and the water vapor barrier performance with the Ar and O₂ flow rates. The roughness of the deposited coatings increased when either the O₂ or Ar flow rate was increased.     

Thermal oxidation of chemical vapour deposited tungsten layers on silicon substrates for embedded non-volatile memory application

This research is targeted to enhance the functionality of bipolar complementary metal-oxide-semiconductor by innovative concepts of embedded resistive random access memory (RRAM) cells integration in the back-end-of-line (BEOL) region. The material of our interest is tungsten oxide as an insulator in RRAM cells and we focussed on the growth and characterisation of closed tungsten oxide layers. In this materials science study, we investigated the tungsten oxidation process under BEOL constraints (< 450 °C). Thin films of tungsten oxide (6-50 nm) were prepared by oxidising, under an atmosphere of one bar oxygen, the chemical vapour deposited tungsten layers on TiN covered silicon wafers. The X-ray photoelectron spectroscopy investigations indicate that the stoichiometric WO₃ grows after oxidation at 300 °C for an hour. The tungsten oxide layers prepared above 300 °C for longer than 15 min were non-stoichiometric. The X-ray diffraction investigations reveal the crystallisation of the WO₃ layers in monoclinic phase above 350 °C when oxidised for longer than 30 min; above 400 °C the (001) growth texture becomes dominant.