绝缘衬底上a-Si∶H膜CW Ar~ 激光结晶

本文用连续氩离子激光对辉光放电法淀积在二氧化硅层上的氢化非晶硅(a-Si∶H)薄膜进行辐照扫描,使a-Si∶H膜结晶。利用金相显微术和透射电子显微术对結晶薄膜的形貌和結构进行了研究,并用等离子刻蚀技术确定结晶度。激光加工时衬底溫度为240℃,扫描速度为2cm/s,束斑直径大约40μm,交叠50％。经功率为4W激光辐照后,样品表面平整光亮,部分区域巴结晶成多晶,相邻的二次扫描的相间区由于溫度低于结晶溫度,仍为非晶态且易被腐蚀掉。激光功率增至6W和7W时,部分区域受损伤成为非晶、微晶和多晶混合体,而相间区已结晶成多晶。适当选择衬底溫度、激光功率和扫描适度可望获得良好的結晶,它对SOI器件的制作是有意义的。     

介质隔离中多晶外延的改进

对于介质隔离的氧化层必须结构致密,缺陷少,以保证较好的隔离特性。通常在外延炉里淀积的二氧化硅层由于各种原因质量较差,有时还会出现多晶生长不上的现象,且厚度及质量难以检测。用热生长法代替淀积法形成的二氧化硅层,结构致密、缺陷少,仅做30分钟的干氧,即可达百伏以上的耐压。介质隔离的反外延时间长,耗源量多,对设备损耗大。用喷头结构可使气流直接喷在硅片上,使源充分利用,从而提高了多晶硅的生长速率,时间由原来的6个多小时缩短为3个多小时,用源量只相当于原来的五分之一左右。且多晶硅的厚度均匀。     

SIPOS-Si界面应力研究

本文用激光光学方法测量半绝缘多晶硅(SIPOS)一硅的界面应力,以研究SIPOS-Si界面结构及界面应力的物理机理。对于氧含量在10～35％的SIPOS薄膜的SIPOS-Si界面应力,我们发现界面应力与氧含量有明显的关系,一般说随氧含量的增加而减小,并且由张应力变为压应力。此外,界面应力还与薄膜的淀积工艺有关;如:温度、淀积速率等。将样品进行高温退火,由于界面应力的热效应将使界面应力显著减少,并转变为压应力。这是高温热处理使SIPOS薄膜再结构的结果。     

SIPOS-Si界面应力研究

本文用激光光学方法测量半绝缘多晶硅(SIPOS)一硅的界面应力,以研究SIPOS-Si界面结构及界面应力的物理机理。对于氧含量在10～35%的SIPOS薄膜的SIPOS-Si界面应力,我们发现界面应力与氧含量有明显的关系,一般说随氧含量的增加而减小,并且由张应力变为压应力。此外,界面应力还与薄膜的淀积工艺有关;如:温度、淀积速率等。将样品进行高温退火,由于界面应力的热效应将使界面应力显著减少,并转变为压应力。这是高温热处理使SIPOS薄膜再结构的结果。     

汽相淀积多晶硅薄膜结构和性质的研究

多晶硅薄膜的制备采用硅烷(SiH_4)热分解化学汽相淀积法。利用透射电子显微镜、扫描电子显微镜和红外光谱仪等手段对膜的微结构进行了研究。我们发观膜的结构特性强烈地依赖于淀积条件,实验结果指出:假如在整个淀积过程的最初阶段采用“低温成核”,就不难获得适合于硅栅MOS集成电路的优质多晶硅膜。当低温成核温度为650℃～700℃,并控制一定的淀积条件,所制得的膜是光亮和均匀的,其晶粒大小约为300～500埃。文中对“低温成核”的机理及多晶薄膜的生长模型也进行了讨论。此外,对多晶膜的光学、电学和介电等性质进行了测量,对多晶硅由于晶粒间界的存在而引起的一系利与单晶硅不同的性质进行了计算和分析,从而为器件设计提供某些有用的理论数据。     

砷离子束感生铂硅化物的形成

本文研究了砷离子感生硅化铂的形成与生长动力学.用150keV的砷离子束轰击在P型、(111)单晶硅上淀积一层铂的薄膜的样品.在铂膜与单晶硅界面附近观察到铂与硅两类原子的混合层.用RBS方法研究混合层的厚度与砷离子的剂量和能量,以及与轰击时样品温度的依赖关系.用X射线衍射测量确认混合层的物相.实验结果说明,样品中存在的杂质如氧及氩将会影响硅化铂的形成与生长.     

多晶硅薄膜生长因素的分析

近些年来,多晶硅薄膜已广泛地应用在半导体器件上,例如大规模集成电路、太阳能电池等。尽管应用的如此广泛,但由干对多晶硅物理特性的了解尚不是十分充分,因而给器件生产带来一定的盲目性。因此,生长优质多晶硅薄膜并弄清楚生长过程中各个因素之间的关系,对研究多晶硅的物理特性是很有必要的。为此,对多晶硅的生长速率与淀积时间的关系、掺杂剂对多晶硅薄膜生长的影响、淀积温度对多晶硅薄膜生长的影响进行了研究和讨论。 采用常规的硅烷热分解化学气相淀积方法(APCVD)生长多晶硅薄膜,用 WDL-31光电温度计测量多晶硅薄膜淀积温度,用6JA…     

Al金属多晶硅纳米膜欧姆接触的制作

利用低压化学气相淀积法(LPCVD)在表面有热氧化二氧化硅的(100)硅衬底上生长80nm厚多晶硅纳米膜,并对其界面进行表征.制作出单层Al金属的欧姆接触样品,在不同退火温度条件下对样片的电阻进行测量.结果表明,退火使欧姆接触的电阻率降低,接触电阻率可达到2.41×10-3Ω.cm2.     

低温湿氮退火对SiO_2-Si界面的影响

用高频C—V和准静态C-V技术研究了低温湿氮退火对SiO_z—Si界面的影响。结果表明,铝淀积后并在铝腐蚀之前的460℃湿氮退火有效地减少了表面电荷和界面态密度。还比较了铝淀积前退火、铝腐蚀前退火和铝腐蚀后退火的效果,证明铝腐蚀前退火给出最小的表面电荷和界面态密度。对结果和退火机理进行了讨论。     

非晶态硒化镉薄膜光电特性的研究

本文报道用真空热蒸发淀积非晶态硒化镉薄膜,研究淀积基底温度及退火处理对薄膜光电特性的影响。光谱实验表明吸收边有随基底温度降低而向长波方向移动的现象,发现淀积基底温度为150℃的样品其光电导与暗电导的比率最高。用超短序列光脉冲对薄膜的瞬态光电导特性进行研究,表明非晶态硒化镉薄膜对ps级超短光脉冲具有良好的瞬态响应,可用作快速光电探测器的光敏材料薄膜。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that