Mo-based EUV multilayer filters with enhanced thermal stability

New Mo-based multilayer structures are proposed, and sample free-standing filters 160 mm in diameter with a transparency of 71% at a wavelength of λ = 13.5 nm are described. The enhanced thermo-oxidative stability of filters with Mo layers is demonstrated as opposed to Zr-based films. It is shown in particular that Mo-based filters can withstand vacuum heat annealing at 800°C for three hours without any optical and structural changes.     

19.5nm极紫外反射镜的研制

介绍了一种用于太阳观测19.5nm极紫外多层膜的研究工作。利用软件对规整的Mo/Si膜系结构进行了优化,拓宽了反射带宽,提高了积分反射率。采用双离子束溅射技术,时间控厚,成功制备了该反射镜。通过同步辐射反射率计测试表明,峰值反射率27.5%,均匀性在1%以内,已初步达到预设要求。     

Interface engineering to decrease interdiffusion and improve thermal stability of EUV multilayer

We use interface engineering technology to obtain high interface quality of extreme ultraviolet （EUV） multilayer. By inserting ultrathin （〈0.5 nm） B4C layer between Mo and Si layers in Mo/Si multilayer, the interdiffusion in the multilayer is decreased obviously and the reflectivity can be estimated to increase by 2%. By inserting a new inert material barrer between Mo and Si layers, the thermal stability of new forming Mo/X/Si/X multilayer is increased significantly. The multilayer is annealed at 500 ℃ for 100 h with the fluctuation of period thickness smaller than 0.1 nm, and the high resolution transmission electron microscopy image also shows that the mirostructure of the multilaver is not changed obviously.     

EUV damage threshold measurements of Mo/Si multilayer mirrors

We present 1-on-1 and 10-on-1 damage threshold investigations on Mo/Si multilayers with EUV radiation of 13.5 nm wavelength, using a table-top laser produced plasma source based on solid gold as target material. The experiments were performed on different types of Mo/Si mirror, showing no significant difference in single pulse damage thresholds. However, the damage threshold for ten pulses is ??60?% lower than the single pulse threshold, implying a defect dominated damage process. Using Nomarski (DIC) and atomic force microscopy (AFM) we analysed the damage morphologies, indicating a primarily thermally induced damage mechanism. Additionally, we studied the radiation-induced change of reflectivity upon damage of a multilayer mirror.     

Computer simulation of blistering in multilayer mirrors for EUV lithography

Progress in extreme UV lithography depends on the quality of multilayer radiation collecting mirrors (made of Mo/Si), in which radiation damage can cause porosity. Accumulation of bulk defects (blisters) is represented by the model of the first order phase transition at a fluctuation stage. Computer simulation of defect distribution functions depending on the sizes and arrangement in layers allows the determination of possible ways for the properties of the layer material properties to deteriorate.     

Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications

Applied Physics A - We present the results of the characterization of Mg/Co periodic multilayers and their thermal stability for the EUV range. The annealing study is performed up to a temperature...     

Design and performance of two-channel EUV multilayer mirrors with enhanced spectral selectivity

In this paper, we present a study on two-channel multilayer mirrors which can operate at two wavelengths in Extreme Ultraviolet (EUV) spectral range. We propose a new method to design two-channel EUV multilayer mirrors with enhanced spectral selectivity. The mirror structure is a stack of two periodic multilayers separated by a buffer layer. We have defined the main parameters which allow adjustment of the distance between different order Bragg’s peak and of wavelength positions of reflectivity minima. Two mirrors have been designed and deposited for solar EUV telescope applications by using this method. The first mirror reflects Fe IX–X line (17.1 nm) and Fe XVI (33.5 nm) lines with attenuation of the He II line (30.4 nm). The second mirror reflects Fe IX–X and He II lines with attenuation of Fe XV (28.4 nm) and Fe XVI lines. Measurements with synchrotron radiation source confirm that, in both cases, for these mirrors, we are able to adjust reflectivity maxima (Bragg peak position) and minima. Such multilayers offer new possibilities for compact design of multi-wavelength EUV telescopes and/or for high spectral selectivity.     

Plasma cleaning of multilayer mirrors in EUV lithography from amorphous carbon contaminations

The feasibility of plasma cleaning of the multilayer mirrors used in 13.5-nm EUV lithography from carbon contaminations is studied. Experiments conducted in electrodeless plasma of the surface-wave low-pressure discharge in helium and hydrogen demonstrated the high rate, efficiency, and selectivity of this cleaning without any damage of the mirror’s upper protection layer, even at the atomic level. The optimal working parameters of plasma cleaning are determined and its possible mechanism is discussed.     

Fabrication and characterization of EUV multilayer mirrors optimized for small spectral reflection bandwidth

Our aim was to produce EUV multilayer mirrors with a small spectral bandwidth ΔE≤3 eV at 70 eV peak energy using UHV electron beam evaporation by varying the thickness ratio (Γ=) between the absorber layer and the bilayer. The deposition process was controlled by in situ soft X-ray reflectometry, and ion-beam polishing as well as substrate-heating methods were applied to reduce the interface roughness. The reflection properties of the Mo–Si multilayer mirrors prepared were characterized by hard and soft X-ray reflectometry and details of the multilayer structure were revealed from cross-sectional transmission electron microscopy. Received: 22 September 2000 / Accepted: 4 October 2000 / Published online: 30 November 2000     

Solution of 111In impurities in the Hf(Zr)3Al2 minority phases of Hf(Zr)4Al3 samples

The hyperfine quadrupole interactions of ¹¹¹In/¹¹¹Cd probes in the polycrystalline isostructural Zr₄Al₃ and Hf₄Al₃ compounds were studied. Strong preference of ¹¹¹In solute for the Zr₃Al₂ and Hf₃Al₂ phases occurring as contaminant fractions in the measured samples was observed.     

Ion bombardment of ordered Zr3Al

The behaviour of the ordered alloy Zr₃Al was investigated by transmission electron microscopy following ion bombardments at temperatures ranging from 30 to 850 K. Utilizing high energy(0.5–2.0 MeV) C⁺, N⁺ and Ar⁺ ion bombardments, observations were made of the irradiation-induced transformation from the ordered → disordered → amorphous states. Information about individual damage cascades was also obtained using both high energy (C⁺. N⁺ and Ar⁺) and low energy (15–120 keV Cu⁺) ion bombardments.     

The Electric Field Gradients in (Zr/Hf)Al3 and (Zr/Hf)2Al3 Intermetallic Compounds Studied by 181Ta- and 111Cd-PAC Spectroscopy

The electric quadrupole hyperfine interactions for ¹⁸¹Hf/¹⁸¹Ta and for ¹¹¹In/¹¹¹Cd probes in polycrystalline ZrAl₃ and Zr₂Al₃ compounds were measured in the temperature range 30–1100 K and compared with the results for isostructural hafnium aluminides. On the basis of the similarities of the numbers, sizes and asymmetries of electric field gradients, lattice site allocations were made. In all matrices, ¹⁸¹Hf/¹⁸¹Ta was found to substitute the Hf/Zr site. The ¹¹¹In/¹¹¹Cd impurities were also assigned to the Hf/Zr site in the compounds (Zr/Hf)Al₃, but appear to substitute the two non-equivalent Al sites in the Zr₂Al₃ and Hf₂Al₃ phases. This revised version was published online in September 2006 with corrections to the Cover Date.     

Optical,thermal and mechanical characterization of Al(III)/Sb(III)-doped tris(thiourea)zinc(II) sulphate crystals

The influence of Al(III)/Sb(III)-doping on the properties of tris(thiourea)zinc(II) sulphate (ZTS) crystals grown by slow evaporation solution growth technique is reported. The as-grown crystals belong to orthorhombic system and cell parameters are, a = 7.77 Å, b = 11.13 Å, c = 15.47 Å, V = 1338 Å³ (Al(III)-doped) and a = 11.1996 Å, b = 7.770 Å, c = 15.5598 Å, V = 1368.3 Å³ (Sb(III)-doped). The structure and the crystallinity of the materials are further confirmed by powder X-ray diffraction analysis. The modes of vibrations of different functional groups present are identified by Fourier transform infrared studies. Thermogravimetric/differential thermal analysis studies reveal the purity of the materials and no decomposition is observed up to the melting point. Surface morphological changes due to doping are observed by scanning electron microscopy. Microhardness study was carried out to elucidate the mechanistic behavior microhardness studies were carried out to elucidate the mechanistic behavior. Second harmonic generation activity is much better in the case of Sb(III)-doping. The specimen is also characterized by dielectric studies.     

质子辐照对极紫外波段滤光片透过率的影响

为了检验应用在极紫外波段空间太阳望远镜上Al滤光片在空间辐照环境下透过率的变化情况,用能量100 keV,剂量为6×1011/mm2的质子束对其进行辐照,利用透射电子显微镜分析了质子辐照前后滤光片的微观结构。实验结果表明:由于质子辐照使滤光片受质子侵蚀后,Al原子被击出发生质量损失,表面形态发生了变化,造成滤光片变薄,从而导致透过率由辐照前的12.1%增大到15.0%,且滤光片的薄厚分布不均匀使透过率曲线出现了次级峰,造成其光学性能的退化。     

The Hall effect in amorphous (Zr0.64Ni0.36)1−x M x alloys (M=Al,Ga)

Values of the room temperature Hall coefficients and electrical resistivity of amorphous melt spun (Zr_0.64Ni_0.36)_1–x Al _x and (Zr_0.64Ni_0.36)_1–x Ga _x alloys forx=0–0.25 are reported. Addition of Al or Ga to Zr_0.64Ni_0.36 dramatically increases the already positive Hall coefficient of this alloy and also increases the electrical resistivity and crystallization temperature.     

Al(111)/Al_3Li(111)的界面性质

运用基于第一性原理的平面波贋势法,计算研究了Al (111)/Al_3Li (111)的界面性质.结果表明:Al (111)/Al_3Li (111)的界面具有三种原子配位关系结构,其中界面处仍保持与基体Al一致的三明治堆垛构型的界面稳定性最好.计算表明,该结构界面最薄弱层,位于Al_3Li (111)内,其分离功最小(约1.53 J/m~2),强度最弱,而基体Al和Al_3Li内部的强度随着到界面距离的增大而逐渐增强.     

The melt structural characteristics concerning the interfacial reaction in SiC(p)/Al composites

We investigated the YAG laser-generated ultrasonic wave in a solid with an array of rectilinear sources in the melting regime. By adapting the melting rectilinear sources, a 31.2 gain factor of amplitude of the excited ultrasound can be obtained for the aluminum (Al) sample in comparison with the ultrasound generated by rectilinear sources in the thermoelastic regime. In the melting regime, the sample surface remains undamaged during the inspection. Calculations and experimental results show that the array characteristics and the detection point will decide the increase of amplitude, center frequency, bandwidth, and directivity pattern of the narrow-band ultrasound signals generated by a melting-source array. Through our research, the array of melting sources is proved to be a useful tool to enhance the generation efficiency and detection sensitivity in nondestructive inspection.     

热原子层沉积氧化铝对硅的钝化性能及热稳定性

原子层沉积氧化铝已经成为应用于钝化发射极和背面点接触（PERC）型晶硅太阳能电池优异的钝化材料．对于基于丝网印刷技术的太阳能电池,钝化材料的钝化效果及其热稳定性是非常重要的．本文在太阳能级硅片上用热原子层沉积设备制备了20nm和30nm的氧化铝,少子寿命测试结果显示初始沉积的氧化铝薄膜具有一定的钝化效果,在退火后可达到100μs以上,相当于硅表面复合速度小于100cm／s．经过制备传统晶硅太阳能电池的烧结炉后,少子寿命能够保持在烧结前的一半以上,可应用于工业PERC型电池的制备．通过电子显微镜观察到了较厚的氧化铝薄膜有气泡,解释了30nm氧化铝比20nm氧化铝钝化性能和稳定性更差的异常表现．