研究辐射与金属靶相互作用和反射测量的小型脉冲X射线激光器的光束聚焦

引言由于产生软 X射线激光器的特点 (没有谐振腔 ,增益介质的不均匀性 ) ,要求仔细研究激光辐射的时空特性和能量特性、它的相干性和光谱成分等。本文根据被照射靶的烧蚀孔形状 ,研究了文献 [1 ]叙述的装置的激光束在球面镜焦散面处的激光束强度的空间分布 ,并研究了软 X射线激光在反射测量中的应用。1　软 X射线激光聚焦时的烧蚀软 X射线激光束聚焦后会达到非常高的辐射强度 ,这就开发了其应用的新可能性。在不久之前的实验[2 ] 中 ,Al的类 L i离子的复合激光器纳焦耳脉冲 (λ=1 5 .47nm)聚焦后产生强度为～ 1 0 7W/cm2 的亚微米尺寸的…     

用激光脉冲列开发小型软X射线激光

1．前言X射线显微镜、X射线光刻等各种实际应用所期待的X射线激光的开发研究正在世界范围内进行。特别是利用固体靶在1kJ以下的照射能量，证实了能产生强的放大自发辐射（ASE），各国集中力量开展用电子碰撞激发机制的类氖Ge离子X射线研究。以确认增益饱和为目的的各种实验成果已有报道。日本理化研究所提出的用激光脉冲列激发X射线激光的方案，已由劳伦斯·里弗莫尔实验室和大皈大学所验证，确认了等离子体逐次有效的加热作用，公认为是一种有效的激发手段。但是，用这种方法产生类氖Ge离子X射线激光（波长19．6nm，23．6nm）也需要几…     

激光辐射与稠密气体靶的相互作用

引言文献[1]提出的使用“喷气”（“puff”gas，即通过细喷嘴喷至真空室的不大气团）作为靶的思想，在一系列应用和基础研究中颇有成效。它在磁约束实验中曾用于获得高温等离子体[1]，并曾用于多光子电离实验[2.3]和谐波振荡[4.5]。文献[6]曾建议使用激光“喷气”作为X射线源。虽然这种建议仅过去三年，但已成功地用于研制短波长激光器[7.8]、隋性气体多童电离光谱学[9~11]和研制X射线光刻辐射源[12]。虽然有如此众多的进展，但是对对象的参数，即“喷气”的激光等离子体，至今日却知之甚微，而且现有的信息只是对于气压不高的“喷气，，［…     

13～14 nm区类Ni氙跃迁X光激光器研究

1 引言目前正积极研究13~14nm区真空紫外激光振荡的可能性，因为在该波长区发展了反射率达到60%的多层膜反射镜的制造方法[1~3]。该区较强激光可用于微光刻、X射线显微术和生物技术等。最近几年正在探讨建立真空紫外激光器的新实验途径。例如，研究了在脉宽0.9~10 ns、能量~0.7 J的Nd∶YAG激光抽运的所谓气体-喷团靶内1~22 nm区的强辐射[4]。这种“光火花等离子体”源早在70年代初讨论过[5]。目前它是为了在1~5nm区产生激光辐射的、形成不压缩、不消蚀等离子体的有前途的装置[6]。P.V.Nickles等人提出了混合抽运源：毛细管放电形成类Ne…     

在高度饱和桌面毛细管放电放大器中以4Hz重复率产生毫焦耳级软X射线激光脉冲

软 X射线激光有别于其它相干软 X射线辐射源的特性是其产生高能脉冲的潜力。由大型光学激光抽运的软 X射线激光输出能量已达几个毫焦耳。然而产生这些软 X射线激光脉冲的激光装置很大 ,而且它们的重复率限于几分钟一次或更少。前几年在研制以较高重复率运转的桌面软 X射线放大器方面已取得重要进展 [1 ]。在最近的工作中已演示用非常紧凑的桌面器件以 4Hz重复率产生毫焦耳量级的软 X射线激光脉冲[2 ] 。该结果在长 34 .5 cm毛细管放电等离子体柱中激发类氖氩电子在 46 .9nm波长上获得。这样的放大长度允许其增益长度乘积比获增益饱和所需…     

液体靶激光等离子体产生X射线

以液体为靶．对激光等离子体产生X射线做了详尽的论述。以液体为靶的激光等离子体产生X射线大大减少了碎片的产生,同时也具有与固体靶几乎相同的转换效率,是一种很有潜力的产生X射线的方法。     

桌面激光器产生X射线

从微波激射器 (maset)发明以来 ,人们就大力研究如何缩短受激辐射光放大的工作波长。随着波长的缩短 ,激射材料中所需能量密度急剧增加 ,这样 ,在波长短到 5 0 nm以下时 ,激射材料必须采用等离子体。可见或近红外波段的激光器常用来产生短波激光研究所需的等离子体 ,虽然也曾使用放电产生的等离子体。在这类实验中 ,将光聚焦在固体靶上形成线状等离子体 (图 1 )。固体蒸发并电离 ,然后膨胀并高速离开靶面。在短暂时间内 (典型值是 2～ 1 0 0 ps) X射线激射沿等离子体线发生 ,激射区域等离子体的温度和密度应满足一定条件 ,范围一般在离靶面…     

利用X射线压缩新的聚变靶

劳伦斯·利弗莫尔实验室正试验新靶设计，这个设计利用短波长激光可能改善聚变靶聚爆的对称性。入射到这种靶上的激光能量首先转变成热X射线，然后由X射线激励靶球聚爆。可是海军研究实验室的波德纳（Stephen Ε. Bodner)说,对于由激光能量直接激励聚爆的其他靶，氟化氢激光器可熊是最好的激励源。他解释说，用1到3微米范围的激光可能得到的较好的对称性应能抵销较短波长激光的其他优点。     

毛细管放电软X射线激光研究进展

近几年来实用型、台式软X射线激光器发展非常迅速，特别是毛细管放电抽运的X射线激光源，已经获得46.9nm近1mJ激光输出，重复率4Hz。该台式激光器在等离子体诊断、物质烧熔等方面已经开展了初步的应用实验。本文首先简介了利用毛细管放电抽运X射线激光器的两种物理机制：电子碰撞机制和三体复合机制。然后着重介绍毛细管放电碰撞机制软X射线激光的研究进展，包括实验方案、实验装置、增益测量实验及初步的应用。对毛细管放电软X射线激光的几个关键性问题进行了讨论。     

毛细管放电激励类氖-氩离子X光激光研究

以类氖 氩离子跃迁线为例 ,应用一维的Lagrangian程序———XDCH研究了毛细管放电碰撞机制激励软X光激光的物理机制 ;对等离子体的Z 箍缩过程和 46 9nm谱线产生增益的条件进行了讨论 ;并分析了毛细管放电装置中产生软X激光的可能性。     

Performance enhancement in inverted polymer solar cells incorporating ultrathin Au and LiF modified ZnO electron transporting interlayer

The performance enhancement of inverted polymer solar cells (PSCs), based on the blend system of regioregular poly(3-hexylthiophene) and [6,6]-phenyl C₆₁-butyric acid methylester, due to incorporating ultrathin Au and LiF interlayer between the front transparent indium tin oxide and a ZnO electron transporting layer was analyzed. The results reveal that a 40% increase in PCE, e.g., from 2.62% to 3.67%, was observed for PSCs made with an optimal Au/LiF interlayer as compared to the one having a bare ZnO electron transporting layer. The presence of Au/LiF-modified ZnO interlayer between ITO and the organic layer helps to improve the charge collection. The absorption enhancement arising from the plasmon resonance of Au nanostructures also contributed to the improvement in PCE. It is shown that PSCs with LiF incorporated ZnO electron transporting layer allow improving cell lifetime, demonstrating <50% decrease in PCE compared to that of the ones with a bare ZnO interlayer after 240 day aging test for cells without encapsulation in air.     

Fluxless Wafer Bonding in Vacuum Using Electroplated Sn–Ag Layers

A wafer-to-wafer bonding process using Sn-Ag solder without any flux is successfully developed. This fluxless or flux-free feature makes void-free and uniform bonding layers possible. This is in contrast to the fluxing process employed in nearly all soldering processes adapted in the electronic industry. With the use of flux, the flux or flux residues are easily trapped in the solder joint, resulting in voids and uneven solder layers. This is particularly true if the bonding area is large, such as the entire wafer. Thus, void-free wafer bonding using solders has never been reported. It is thus clear that the key to achieve void-free wafer soldering is to eliminate flux completely. The new fluxless process is performed in a vacuum furnace built in house to inhibit solder oxidation. To prevent oxidation during solder manufacturing, a thin Ag capping layer is plated over the Sn layer right after the Sn layer is plated over an entire 2-in silicon wafer having Cr/Au under bump metallurgy (UBM). This outer Ag layer is critical in preventing the inner Sn layer from oxidation when the wafer is exposed to air. The Si wafer with Cr/Au/Sn/Ag structure is bonded with another Si wafer with Cr/Au at 240degC in the vacuum furnace. To evaluate the joint quality and study the microstructure and composition, scanning acoustic microscopy (SAM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) are used. A solder joint with only 1% void area is accomplished. The initial success of this process illustrates that it is indeed possible to bond entire wafers together with a thin metallic joint of high quality. This fluxless bonding technique can be extended to bonding wafers of different materials for new device and packaging applications.     

Microstructure and texture of free-standing Cu-line patterns

Free-standing discontinuous Cu-line patterns varying in line widths and interline distances in the range of a few micrometers were manufactured by combining photolithography and electrochemical deposition. Two principally different seed layers, polycrystalline Au and X-ray amorphous Ni-P, were applied prior to electrodeposition of the Cu lines as well as continuous Cu films, which were deposited as reference. The effect of the seed layer and the influence of the pattern design on surface topography and morphology of the deposits were studied by means of light optical and scanning electron microscopy (SEM). The growth behavior is related to the developing crystallographic texture of Cu-line patterns and continuous films, as determined from calculated orientation distribution functions (ODFs) on the basis of X-ray diffraction (XRD) pole figure measurements. While strong crystallographic textures of Cu lines on polycrystalline Au were observed with pattern-dependent differences to continuous films, almost no preferred grain orientations develop both for Cu lines and corresponding continuous films deposited on amorphous Ni-P.     

基于共沉积技术的AgTCNQ的有机双稳态器件

采用共沉积技术制备了AgTCNQ薄膜,并进行了红外、紫外光谱表征.利用微电子工艺制备了基于AgTCNQ薄膜的有机双稳态器件.研究发现,Ti/AgTCNQ/Au双稳态器件具有可逆、可重复的开关存储特性.将器件从初始的高阻态转变为低阻态的正向开关阈值电压为3.8～5V,将低阻态转变为高阻态的负向阈值电压仅为-3.5～-4.4V,与通常的CuTCNQ器件相比较小.这种基于AgTCNQ交叉结构的有机双稳态器件可应用于非易失性有机存储器.     

Improved ohmic contact to n-type 4H and 6H-SiC using nichrome

Results are reported for ohmic contacts formed on n-type 4H and 6H-SiC using nichrome (80/20 weight percent Ni/Cr). The electrical characteristics of these NiCr contacts are similar to those of contacts formed on 6H-SiC using pure Ni (∼1×10⁻⁵Ω-cm² for moderately doped material), but the contacts exhibit significant improvement with regard to physical stability. Composite Au/NiCr contacts exhibit good stability during long-term anneals (∼2500 h) at 300°C without the requirement of a diffusion barrier layer between the NiCr ohmic contact layer and the Au cap layer. In addition, the use of NiCr results in success rates near 100% for direct wire bonding to the Au cap layers. Characterization of the contacts by Auger electron spectroscopy, Rutherford backscattering spectroscopy, and transmission electron microscopy provides an explanation for the observed behavior.     

基于共沉积技术的AgTCNQ的有机双稳态器件

采用共沉积技术制备了AgTCNQ薄膜,并进行了红外、紫外光谱表征.利用微电子工艺制备了基于AgTCNQ薄膜的有机双稳态器件.研究发现,Ti/AgTCNQ/Au双稳态器件具有可逆、可重复的开关存储特性.将器件从初始的高阻态转变为低阻态的正向开关阈值电压为3.8～5V,将低阻态转变为高阻态的负向阈值电压仅为-3.5～-4.4V,与通常的CuTCNQ器件相比较小.这种基于AgTCNQ交叉结构的有机双稳态器件可应用于非易失性有机存储器.     

Fluxless process of fabricating In-Au joints on copper substrates

Based on the oxidation-free fluxless bonding technology, we have developed a bonding process to manufacture In-Au joints on copper substrates. 4 mm×4 mm Si blank dice and 6 mm×6 mm copper substrates are used. The dice are deposited with indium-rich Au/In/Cr multilayer structure in a single high vacuum cycle to prevent oxidation. Right after deposition, the outer Au layer interacts with the In layer to form AuIn₂ intermetallic compound. This compound is quite stable and thus can protect the In layer against oxygen penetration when it is exposed to ambient. On the other hand, it can easily be dissolved by the molten In during the bonding process. The substrate is deposited with Cr and Au. The dice are bonded to the substrates at 180°C in inert environment. Nearly void-free joints have been obtained as examined by a 75 MHz Scanning Acoustic Microscope (SAM). Cross sections of several samples are studied using SEM and EDX to identify the microstructure and composition of the joints. Shear test has been performed according to MIL-STD-883C. All the well-bonded devices meet the shear test force requirement. Despite the large mismatch on the thermal expansion coefficient between silicon and copper, no die cracking is observed on the 30 samples produced. To assess further endurance, two samples underwent thermal cycling test between -50 and 120°C for 20 cycles, SAM examination indicates that the joints incur little degradation after the test. This bonding method requires neither flux nor scrubbing action. It is thus particularly attractive for bonding devices that cannot be exposed to flux     

RF device package method using Au to Au direct bonding technology

This paper presents design, fabrication and evaluation of a wafer level MEMS (Micro Electro Mechanical System) encapsulation using an Au to Au direct bonding with wrinkle patterned layer. For the effective encapsulation, the optimal bonding condition, the bonding temperature 350 °C, the bonding pressure 58 MPa and the duration time 30 min, was developed and used in this paper. We briefly evaluated the bonding strength of test wafers after the bonding test. For RF (Radio Frequency) device packaging, we effectively interconnected Au CPW (Coplanar Waveguide) lines to feedthroughs and measured the RF characteristics. Measured insertion loss of the packaged CPW line was −0.11 dB at 2 GHz. The glass wafer having patterned Au sealing lines was also bonded and has been dipped in the acetone solution for 24 h to examine the leakage of bonding wafer. After 24 h dipping, any leakage point has not been observed at the sealing line and inside the cavity. These results showed that our Au to Au direct bonding method is very reliable and suitable for RF device packaging.     

Improved performance of CH3NH3PbI3 based photodetector with a MoO3 interface layer

Planar CH₃NH₃PbI₃ perovskite based photodetectors are fabricated by a facile and low-cost one-step method. The devices show broad spectral photoresponse from the ultraviolet to whole visible region and the performance can be significantly improved by the introduction of a bipolar transporting MoO₃ interface layer between CH₃NH₃PbI₃ film and Au electrode. The photocurrent of the device with an optimized MoO₃ layer is about twice that of the reference device without MoO₃ layer, which results in a high ON/OFF current ratio of 5.9 × 10³ at 5 V. Besides, slightly increased photoresponse speed is also found in the optimized device with rise time and decay time of 21.6 and 9.9 ms, respectively. The improvement can be attributed to the improved hole and electron collection efficiency and the quickly filled in or emptied trap states at the CH₃NH₃PbI₃/Au interface due to the introduction of the bipolar transporting MoO₃ layer.     

电子束蒸发制备平板偏振膜激光损伤特性研究

采用电子束蒸发沉积技术制备了平板偏振膜。用Lambda900分光光度计测试了其光学性能。在中心波长1053 nm处P偏振光的透过率TP>98%,S偏振光的透过率TS<0.5%,消光比TP/TS>200∶1,带宽约为20 nm。用波长1064 nm,脉宽12 ns的脉冲激光进行损伤阈值测试,获得P偏振光的损伤阈值为17.2 J/cm2,S偏振光的损伤阈值为19.6 J/cm2。用Nomarski显微镜对薄膜的损伤形貌进行观察,并用Alpha-500型台阶仪对损伤深度进行测试。结果表明,P偏振光的激光损伤为界面损伤与缺陷损伤,而S偏振光的激光损伤主要是驻波电场引起的界面损伤,界面损伤发生在偏振膜表面第一层与第二层界面处,缺陷损伤发生在偏振膜内部。