氢气直流放电的等离子体数值模拟研究

针对低气压、弱电离条件下的氢气放电,建立了二维直流放电模型,建模中修正了有关文献中边界条件的不足,在阴极处,引入了金属电子溢出功和二次电子发射系数来表征电子与离子密度之间的关系;同时由动理论表征了电子能量的分布,依据双流体理论,以作者所分析确定的主要影响低气压、弱电离条件下氢气放电的11种碰撞反应为基础,进行了模拟计算.得出了迁移率、极间距和最小击穿电压间的对应关系,并将模拟曲线与标准的帕邢曲线进行了对比,得到了吻合的结果.     

Ultralow-k silicon containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

Low dielectric constant materials as interlayer dielectrics (ILDs) offer a way to reduce the RC time delay in high-performance ultra-large-scale integration (ULSI) circuits. Fluorocarbon films containing silicon have been developed for interlayer applications below 50-nm linewidth technology. The preparation of the films was carried out by plasma-enhanced chemical vapor deposition (PECVD) using gas precursors of tetrafluorocarbon as the source of active species and disilane (5 vol.% in helium) as a reducing agent to control the ratio of F/C in the films. The basic properties of the low dielectric constant (low-k) interlayer dielectric films are studied as a function of the fabrication process parameters. The electrical, mechanical, chemical, and thermal properties were evaluated including dielectric constant, surface planarity, hardness, residual stress, chemical bond structure, and shrinkage upon heat treatments. The deposition process conditions were optimized for film thermal stability while maintaining a relative dielectric value as low as 2.0. The average breakdown field strength was 4.74 MV/cm. The optical energy gap was in the range 2.2–2.4 eV. The hardness and residual stress in the optimized processed SiCF films were, respectively, measured to be in the range 1.4–1.78 GPa and in the range 11.6–23.2 MPa of compressive stress.     

激光诱导镍等离子体发射光谱Stark展宽和电子密度的空间分辨特性

在大气环境下利用脉冲Nd:YAG激光532nm输出烧蚀Ni靶,产生了激光等离子体。在350-600nm波长范围内测定了激光诱导等离子体中Ni原子的空间分辨发射光谱。得到了385.83nm发射光谱线的Stark展宽及其随径向的变化特性。由发射光谱线的强度和Stark展宽计算了等离子体电子密度,并讨论了激光等离子体的空间演化特性。结果表明,在沿激光束方向上,当距离靶表面0-2.5mm范围内变化时,谱线的Stark展宽、线移和电子密度都随距靶面距离的增大而先增大,在离靶面约1.25mm处时达到最大值,之后随距离的进一步增大而减小;电子密度在0.1-3.0 1016cm-3范围内变化。     

等离子体显示驱动技术发展

等离子体显示技术作为平板显示技术领域重要的分支．面对激烈的市场竞争，在降低成本和提升性能方面承受着巨大的压力。由于驱动电路单元占PDP系统总成本的主要部分，因此，其技术发展变化很快。本文从驱动工作波形的优化、专用集成电路的设计、图像的处理和高分辨率的应用等方面分别介绍了等离子体显示驱动技术近年来主要的发展情况，包括在低成本的设计、显示质量的提高等方面所作的努力。其中．如何调整重置期波形以达到高速、可靠的寻址的目的是本领域的重点研究工作。     

Effect of High-Density Plasma Process Parameters on Carrier Transport Properties in <Emphasis Type="Italic">p</Emphasis>-to-<Emphasis Type="Italic">n</Emphasis> Type Converted Hg<Subscript>0.7</Subscript>Cd<Subscript>0.3</Subscript>Te Layer

Exposure of p-type HgCdTe material to Ar/H₂-based plasma is known to result in p-to-n conductivity-type conversion. While this phenomenon is generally undesirable when aiming to perform physical etching for device delineation and electrical isolation, it can be used in a novel process for formation of n-on-p junctions. The properties of this n-type converted material are dependent on the condition of the plasma to which it is exposed. This paper investigates the effect of varying the plasma process parameters in an inductively coupled plasma reactive ion etching (ICPRIE) tool on the carrier transport properties of the p-to-n type converted material. Quantitative mobility spectrum analysis of variable-field Hall and resistivity data has been used to extract the carrier transport properties. In the parameter space investigated, the n-type converted layer carrier transport properties and depth have been found to be most sensitive to the plasma process pressure and temperature. The levels of both RIE and ICP power have also been found to have a significant influence.     

电磁波在等离子体中的热致非线性衰减

研究了电磁波对等离子体进行加热所产生的非线性效应,分析了电磁波在等离子体中传播的热致非线性衰减,通过与线性衰减的计算结果进行比较,指出当电磁波频率较低且传输距离较远时线性计算产生较大误差,必须考虑电子温度升高引起的非线性衰减,并且分析了非线性衰减随频率、入射电波场强、传输距离等的变化关系,指出在一定条件下,电波对等离子体的加热可使电波的非线性衰减小于线性衰减。     

等离子（水介质）切焊机逆变电路的研制

逆变电路在等离子（水介质）切焊机中具有重要作用。通过逆变电路的整流和稳流,实现可调整的、稳定的功率输出是研制的重点。实际测试表明,本电路能使等离子水介质切焊机稳定持续地工作。     

非制冷红外焦平面阵列读出电路的BCB牺牲层接触平坦化(英文)

研究了一种基于BCB材料的牺牲层接触平坦化技术,用于红外焦平面阵列Post CMOS工艺之前对读出电路表面的平坦化,以利于微测辐射热计微桥阵列与读出电路的集成。利用该方法成功将2μm的电路表面突起,平坦化为表面起伏56 nm的平面,可替代会给器件带来颗粒和损伤的化学机械抛光(CMP)技术。并在该平坦层上方成功进行了非晶硅敏感薄膜的沉积、微桥结构的图形化以及同时作为牺牲层的BCB的释放。通过实验研究了BCB膜层的厚度与转速、固化温度的关系,实验发现BCB的收缩率随温度小范围变化,约为30%。研究了BCB的等离子刻蚀特性,表明该材料适合用等离子刻蚀的方法进行接触孔的刻蚀和牺牲层释放。最后,利用BCB牺牲层接触平坦化技术成功地在读出电路(ROIC)芯片上制作了160×120面阵的非制冷红外焦平面阵列。     

低频Alfvén波谱与冷等离子体的非共振作用研究

本文讨论了低频率Alfvén波谱与冷等离子体的非线性相互作用。研究表明,对于多个低频Alfvén波,在波的振幅相对于背景磁场较小时,随着时间的增加,粒子动理学温度的各向异性会降低;随着振幅的增加,平行方向的动理学温度不断升高,且在A2=0.1处,平行方向的动理学温度将超过垂直方向的动理学温度。     

Plasma etching of copper films at low temperature

Experimental verification of a low temperature (<20 °C), reactive plasma etch process for copper films is presented. The plasma etch process, proposed previously from a thermochemical analysis of the Cu-Cl-H system, is executed in two steps. In the first step, copper films are exposed to a Cl₂ plasma to preferentially form CuCl₂, which is volatilized as Cu₃Cl₃ by exposure to a H₂ plasma in the second step. Plasma etching of thin films (9 nm) and thicker films (400 nm) of copper has been performed; chemical composition of sample surfaces before and after etching has been determined by X-ray photoelectron and flame atomic absorption spectroscopies.