GaN外延结构中微区应变场的测量和评价

 采用电子背散射衍射(EBSD)技术,测量GaN/蓝宝石结构中的弹性应变场.将EBSD菊池衍射花样的图像质量IQ值及小角度错配作为应力敏感参数,表征GaN-Buffer层-蓝宝石结构中的晶格畸变和转动,显示微区弹性应变场.在GaN/蓝宝石系统中,弹性应变的影响范围大约200×700nm.采用快速傅立叶变换(FFT)提取菊池花样的衍射强度,识别GaN外延结构中的应变/无应变区域.     

Texture characterization of Cu interconnects with different Ta-based sidewall diffusion barriers

X-ray diffraction is used to assess the texture of narrow lines and study the impact of different sidewall diffusion barrier materials. All the Ta-based barriers developed a strong 〈1 1 1〉 texture in the scaled geometry, with little effect from sidewall growth. Comparisons were made with blanket wafers, demonstrating the pined grain structure in the narrow lines and contrasting change in texture due to re-crystallization in the unconstrained film. Furthermore, patterned lines showed significant anti-symmetric plane distribution influenced by high strains and twinning along the lines.     

一种镍基高温合金的碳化物析出与转化动力学

采用化学分离联合衍射定量分析法,对多相镍基合金进行了定量相分析研究,得到了850—1000℃下MC的分解和M_(23)C_6,M_6C的析出与热暴露时间的双曲线型变化规律。热暴露过程中M_(23)C_6的元素组成一直在变化,刚析出时为(Cr_(0.67)Mo_(0.13)Ni_(0.13)Co_(0.07))_(23)C_6,其后Cr量增高,Mo,Ni和Co量减少,最终组成为(Cr_(0.88)Mo_(0.07)Ni_(0.03)Co_(0.02))_(23)C_6。热暴露温度愈高,M_(23)C_6达到最终组成状态愈快。     

PdRhO2 formation during the air oxidation of a Pd-15Rh alloy

The surfaces of air-oxidized Pd-15Rh alloys have been examined by X-ray photoelectron spectroscopy (XPS) and by Raman spectroscopy. The XPS results indicate that the near-surface region of samples oxidized in the temperature range 1075 to 1125 K contains Pd in both the +2 and +1 oxidation states and Rh in the +3 oxidation state. The ratio of Pd (I) to Rh (III) is found to be 11. Raman spectra confirm that two Pd-containing phases, PdO and PdRhO₂, are present in the near-surface region and eliminate the possibility that Rh₂O₃ is present. Also, a resonant Raman effect is observed in anhydrous PdO for exciting wavelengths in the vicinity of 500 nm.     

高空间频率向列相液晶二进制光栅

研究了向列相液晶在空间变化电场作用下的电光特性。模拟了向列相液晶相位光栅的旨向矢分布。随着光栅空间频率的增加条纹电场变得很重要，而且衍射方式也发生了变化。分析了光栅的光学性能并进行了实际测量。     

高斯型激光束在圆孔衍射过程中的光束畸变

由于激光畸变所产生的现象及其形成的物理机制十 分丰富,对畸变激光传输特性的研究已然成为一个重要的光学类课题。对此本文将以激光的 圆孔衍射作为切入,采用Zernike多项式函数拟合相位畸变元件的方法,探讨具有高斯型分布 的激光束在圆孔衍射过程中的光束畸变。进一步分析波长、传播距离及函数的阶数对光束畸 变的影响。结果显示,在畸变影响下,由于相散畸变因子作用导致光束 发生对称性退化,引起光束发生分裂,中心光强位置发生偏移,产生像散和离焦畸变现象。 而Zernike多项式函数中q 值会显著影响畸变中光束发生分裂的数量,且随激光波长和传播距离的增大,其畸变影响增 强,像散和离焦变得越明显。     

掩模版复印工艺图形畸变分析与改进

批量化、低成本的掩模版复印工艺常被用于LED领域。在微米级图形的掩模版复印工艺中,受玻璃基板平面度的影响,光学衍射效应会导致图形发生畸变。为消弭复印工艺中的图形畸变,从光学衍射理论展开分析,提出通过调整光刻曝光剂量和光刻胶层厚度来提升掩模版复印工艺水平的方法。实验实现了4μm圆形图形掩模版的复印制作,结果表明该方法可以显著提升微米级图形的掩模版复印工艺水平,降低掩模版的制作成本。     

金属/介质膜脉宽压缩光栅研究进展

超短超高能量脉冲激光作为研究光和物质相互作用的有力手段得到了广泛研究。啁啾脉冲放大系统是产生这种激光的关键部分,其中脉宽压缩光栅作为啁啾脉冲放大系统的核心组成器件,具有至关重要的作用。金属/介质膜光栅具有高衍射效率、宽工作带宽、高激光损伤阈值等优良特性,受到了广泛关注。详细综述了金属/介质膜脉宽压缩光栅的发展概况,重点分析了金属/介质膜光栅的设计原理和制作工艺,展望了金属/介质膜光栅的发展前景,旨在增进对金属/介质膜脉宽压缩光栅的了解。     

Fixed-angle, energy-dispersive x-ray reflectivity measurement of thin tantalum film thickness

In this work, we employed a fixed-angle, energy-dispersive x-ray reflectivity technique to obtain the thickness of thin tantalum films (examples <9 nm) within seconds using a conventional, low-energy x-ray copper or chromium source (20 kV/20 mA/400 W). We compared this fixed-angle, energy-dispersive result with more conventional fixed-energy (monochromatic source), angular-dispersive x-ray reflectivity to establish the validity of the energy-dispersive method. This x-ray technique may be particularly useful for the metrology of growing thin-barrier layers, atomic-layer passivation, and seed-layer measurements in future microelectronics applications. Currently, thickness precision is limited by modeling assumptions and the energy discrimination available from x-ray detectors.     

Band gap engineering by substitution of S by Se in nanostructured CdS1−xSex thin films grown by soft chemical route for photosensor application

Ternary alloys of CdS_1−xSe_x (x=0, x=0.2, x=0.4, x=0.6, x=0.8, x=1) thin films were prepared on to glass substrates by a simple and economical soft chemical route (chemical bath deposition) at 50° to 80 °C in air. The as-grown films were characterized by optical and electrical measurement systems, X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDAX) and SEM (scanning electron microscopy). The optical study reveals shift in the absorption edge towards the higher wavelengths, i.e. the band gap decreases as a function of ‘x’ (quantity of selenium in the bath). I–V measurement of CdS (resulted when x=0), CdS_1−xSe_x (x=0.2, x=0.4, x=0.6, x=0.8) and CdSe (resulted when x=1) thin films under dark and illumination conditions (60 W) were measured. Increase in photoconductivity is observed, suggesting its applicability in photosensor devices. Electrical resistivity shows semiconducting behavior and activation energy decreases. The XRD patterns reveals that deposited thin films have hexagonal mixed structure. EDAX confirmed the compositional parameters. SEM images showed uniform deposition of the material over the entire glass substrate.