Simultaneous aluminum—Silicon metallization by ion-probe-controlled electron beam evaporation

an industrial process for aluminum-silicon metallization using two rate-controlled electron beam evaporators which operate simultaneously is described. The silicon source is controlled through direct measurement of the deposition rate with a quartz crystal monitor. For aluminum the ion current produced by the primary electron beam serves to measure the deposition rate.The ion back-stream measurement method for control of the evaporator is discussed and a typical run is described. The reproducibility of the silicon content produced with this method is investigated. The coating geometry was designed to optimize the uniformity and the step coverage of the deposited films; for this purpose eccentrically located evaporation sources were used. The results achieved for uniformity and coverage of various oxide steps with cold and heated substrates are demonstrated. An investigation of MOS devices with respect to radiation damage due to the electron beam evaporators shows how these sources can be used to coat highly sensitive gate oxides.     

Dünnschichtfilter in der Telekommunikation

Market forces are pushing the performance of optics to their limits. Optical components must be developed to provide the best possible combination of manufacturability, performance and price. One vital step to success in creating WDM optics lies in a discipline that is often overlooked or misunderstood – coating engineering. A key technology for controlling light in WDM systems is the optical filter, which performs functions from simple filtering in multiplexers and demultiplexers, to more sophisticated functions in optical amplifiers, modulators and test equipment. The basic tool of multiplexing and demultiplexing devices, thin film filters offer accurate center wavelength, broad flattop passband and high isolation from adjacent and nonadjacent channels. Thin film filters are widely used for gain flattening, band splitting, C and L band separation and combining amplifier‐pump beams. Choosing the right thin‐film‐deposition process is essential for the efficiency and productivity of vacuum coating systems. LEYBOLD OPTICS has developed and optimized a comprehensive range of vacuum coating processes and process tools. LEYBOLD OPTICS has been proven the ability of producing shift‐free coatings on large substrate areas by means of PIAD (Plasma Ion Assisted Deposition) in many applications over the past ten years. The low loss and stress values achieved, especially with silica and tantala films, allows besides the production of narrow band pass filters (DWDM, CWDM) also the production of gain flattening filters (GFF). PIAD is considerably improving the properties of evaporated thin films by high energy ion bombardment during the growing of the film. PIAD allows to produce dense shift free thin films with high refractive index, good adhesion and extremely low absorption. With the Advanced Plasma Source (APS) LEYBOLD OPTICS has developed a high power plasma source for PIAD. The APS provides high ion current densities over a large surface area in a neutral plasma to produce high quality layers at a high productivity.     

Optical monitoring of thin film properties using in-situ measurement of transmittance and reflectance

Having a good reproducibility and uniformity of the coating properties is a mutual challenge for all coating processes. To face this challenge adequately, it is not only necessary to have accurate control of the coating process but also to have the capability to monitor the optical properties of the coating layers during or directly after deposition. Especially in sensitive multi-layer products produced by large area coating technology, small uniformity variations may give rise to a variation in the visual appearance or other deviations from the product requirements. It becomes necessary to monitor the individual layer thicknesses, requiring sensitive and accurate optical measurement techniques that offer nanoscale precision over large areas. This demand for sensitivity and accuracy puts a strain on the limits of existing in-line measurement capability. The objective of this paper is to discuss some of the measurement problems and give practical solutions to improve accuracy and repeatability of in-situ transmittance and reflectance measurements for optical monitoring of thin film properties.     

Balanceregelung für reaktives Magnetronsputtern zur optischen Großflächenbeschichtung

Best prerequisites for long term stable optical coating are given by reactive Dual Magnetron Sputtering. Requirements for components and techniques for architectural Low‐E coating and TCO coating are discussed. Reliable process stabilization at high deposition rates is possible using Plasma Emission Monitor (PEM) control circuits. The use of multichannel PEM control allows a balance control to improve both the film thickness uniformity and reproducibility of working points for large area coating on glass or web. Examples of horizontal and vertical glass coater for deposition of optical multilayers for different applications are presented.     

The correlation between mechanical stress, thermal shift and refractive index in HfO2, Nb2O5, Ta2O5 and SiO2 layers and its relation to the layer porosity

We present extended experimental material about optical and mechanical properties of oxide optical coating materials, deposited by electron beam evaporation, ion and plasma ion assisted evaporation, sputtering and ion plating. A clear correlation between these experimental data is established and understood as being caused by the different degree of the porosity of the films. This assumption has been verified by investigation of the layer structure and accompanying simulations of the effect of porosity on refractive index, layer stress and thermal shift. As a practical conclusion, we find that a certain pore fraction in the films is essential in order to get a valuable balance between optical and mechanical coating properties.     

脉冲电弧源的发射特性建模

脉冲电弧源是脉冲电弧离子镀方法制备薄膜的重要部件，其发射特性是影响薄膜均匀性的重要因素，本文从理论出发，建立脉冲电弧源发射特性的数学模型，编程计算得到理论的均匀性曲线，与实际的沉积薄膜厚度的均匀性对比，结果表明：脉冲电弧源的蒸发特性可以等效于多个面源的叠加，每一个面源发射的离子密度空间分布符合余弦定律。     

Anomalous optical absorption in dielectric thin films deposited by electron bombardment

The advantages of electron bombardment sources over conventional resistance-heated ones for the deposition of dielectric films can occasionally be outweighed by the occurrence of anomalous optical absorption.Work is described which attempts to identify the cause of this unwanted absorption. A charge analyser was developed which showed that relatively large electron currents can accompany the vapour stream emanating from this type of source. The resulting electron bombardment of the substrate during film deposition apparently gives rise to “colour centre” types of absorption phenomena in the condensed film. Although the mechanism of this process is not fully understood, experimental results are presented which demonstrate the importance of the effect in optical coating technology and show how the absorption can be either eliminated or enhanced by controlling the deposition conditions.     

Inverted Cylindrical Magnetron Sputtering

The shape of inverted cylindrical magnetrons makes them ideal for coating a variety of optical components having non‐planar geometries such as prisms, gratings and spherical lenses. In addition, combining dual cathode mid frequency unbalanced magnetron sputtering with the cylindrical geometry produces a unique source for ion enhanced deposition on planar substrates located at the ends of the cathode. Using a 330 mm diameter source, thickness uniformity on stationary substrates of ± 0.25 % over a diameter of 160 mm and ± 1.3 % over 200 mm can be achieved. SiO₂ and Ta₂O₅ deposited on Si have indices of refraction at a wavelength 632 nm of 1.47 and 2.13 respectively and dispersion similar to those reported for ion assisted processes. The off‐axis nature of this arrangement makes such sources particularly useful where the acceleration of negative ions produced at the target surface can damage sensitive materials such as OLEDs.     

Steady-state direct-current plasma immersion ion implantation using an electron cyclotron resonance plasma source

We have developed a new direct-current (DC) plasma immersion ion implantation (PIII) technique by using a conducting grid positioned between the plasma source and sample chuck. In order to decrease the working gas pressure and increase the plasma density, an electron cyclotron resonance (ECR) plasma source was used in our experiments. In this paper, the experimental parameters and results pertaining to DC-PIII using an ECR plasma source are described. The uniformity of the ion dose and the energy monotonicity are discussed. Our experimental results indicate that DC-PIII is a novel and potentially useful technique for planar sample processing, particularly in microelectronics applications.     

硅基体表面无钯活化化学镀镍工艺

硅材化学镀镍的活化是为了获取金属原子沉积中心,但现有的活化工艺存在种种不足。金纳米粒子具有小尺寸效应、表面与界面效应,呈现出良好的催化活性。采用金纳米粒子对硅基体进行活化后化学镀镍,并采用浸泡腐蚀试验,SEM及EDS测试将其与传统的钯活化法对比,研究了活化后的沉积速度及镀层形貌、结构、耐腐蚀性能,结果表明：金纳米粒子活...     

Effect of stress on performance of dense wavelength division multiplexing filters: optical properties

Thin-film filters used for dense wavelength division multiplexing (DWDM) applications are processed by a variety of deposition techniques, including ion-beam sputtering. Ion-beam sputtering produces high-quality coatings and provides flexibility of coating materials. However, DWDM filters consisting of oxide films that are reactively deposited by ion-beam sputtering, as in most sputter techniques, typically exhibit high levels of compressive stress. This affects the optical characteristics of the filters. Details of the filter passband characteristics and wave-front distortion illustrate the influence of the stress. Spatial variation of the stress on the filter surface causes the filter center wavelength to have spatial variation, and it causes the filter to have an asymmetric passband characteristic.     

Improving the structural quality and adhesion of functional coatings

In this paper a method of improving the structural quality and adhesion of functional coatings due to the pulsed mode of operation of a vacuum arc plasma source is described. The experiments were carried out by producing a carbon-based coating on a molybdenum substrate by spraying a graphite cathode in the benzene vapors. Plasma flow control is provided by alternating connection of two power sources, which allows variable closure of electron and ion currents on the substrate. This mode of operation allows to alternate the mode of heating and active diffusion of particles into the substrate with the mode of their deposition, as well as to provide the process of formation and annealing of the coating layers.     

Prozesse mit hoher Plasmastromdichte und unterschiedlichen Verdampfungsquellen

The hot filament supported high current discharge can be used with various process steps. During the heating cycle, intense electron bombardment provides a soft and efficient energy source. In triode etching the high plasma density improves the throwing power and reduces the arcing problem on oxide inclusions from preceding grinding steps. For the coating cycle the high current density can be fitted into different deposition processes. Activated reactive ion plating is done with a high voltage electron beam gun. But one can also combine the high current density plasma with a magnetron to produce a high plasma density on the substrate and solve the problems of reactivity of this vapor source. Alternatively the high current density plasma can also be used to drive a CVD-reaction. Several of these processes can be combined to hybrid deposition technologies. A few examples of coating realisations and performance in the different processes will be given.     

Microstructural evolution of titanium nitride (TiN) coatings produced by reactive ion beam-assisted, electron beam physical vapor deposition (RIBA, EB-PVD)

Titanium nitride (TiN) coatings have been successfully deposited on 304 stainless steel substrates by reactive ion beam-assisted, electron beam-physical vapor deposition (RIBA, EB-PVD). The hardness values of the TiN coatings varied from 800 to 2500 VHN depending on the processing condition. The lattice parameter and hardness variation were correlated with processing parameters such as: deposition rate, bias, ion source energies, process gas, substrate temperature, and coating composition. The hardness of the TiN coatings increased with increasing ion energy. The ion energies combined with the deposition rate were the limiting factors controlling the degree of surface texturing. Surface texturing was only observed for those coatings deposited >8 Å/s.     

Mach-Zehnder电光调制器产生多波长光源的实验研究

随着对光纤通信容量需求的不断增长,DWDM系统和L波段光器件成为当今研究的热点,多波长光源作为重要的有源器件倍受青睐。本文研究了基于Mach-Zehnder结构的电光强度调制器的理论模型,利用公式仿真得到在一定微波功率调制下强度调制器输出的扩频光谱。实验研究了M-Z结构的集成电光波导强度调制器光波长1550nm处10GHz、15GHz、20GHz扩频的实现,对理论分析所得的输出光谱与实际系统的输出光谱进行比较,发现谱线情况较一致。在调制频率10GHz,调制深度C=1.39,V=2.98V时,输出光谱中可清楚观察到正负三阶等频率间隔的边波带,尤其是一阶边波带与中心波长峰值功率几乎相等,可实现三路光源等功率输出。     

等离子钴基熔覆层的组织和性能研究

等离子熔覆技术是采用等离子束为热源,在金属表面获得优异的耐磨、耐蚀、耐冲击等性能的新型材料表面改性技术。本工作对低碳马氏体钢表面进行等离子熔覆处理,研究钴基合金熔覆层的显微硬度、金相组织。研究结果表明:钴基合金熔覆层的硬度达942HV。熔覆层组织主要由树枝晶和孢状晶粒组成,熔覆层与基体界面结合良好,无裂纹。     

注入氮离子的SiC涂层阻氢性能研究

利用离子束混合－离子注入（Ar^ ）和磁控溅射相结合的实验技术在HR－1不锈钢基体上制备了注入N^ 的SiC涂层，并用表面分析手段对所制备涂层的表面形貌，剖面形貌、相结构，表面成分，表面元素的化学态进行了分析，结果表明：制备的涂层结构致密，表面平整、膜层成分均匀；涂层与基体之间形成了一明显的过渡层，增强了涂层和基体之间的结合力，用二次离子质谱（SIMS）对充氘涂层的阻氢性能进行了定性分析，结果表明，涂层元素与氢形成稳定的化学键，抑制了氢的扩散和迁移，使得涂层具有一定的阻氢能力。     

Plasmasensorik in gepulsten PACVD-Plasmen

Plasma sensor measurement in pulsed PACVD-Plasmas In order to measure local plasma parameters as electron and ion density, electron and ion temperature or plasma potential of inert plasmas Langmuir sensors are used. In practical applications Langmuir sensors showed significant sensor signs when the sensor surface was modified by coatings or pollution [5 – 16]. This effect will be utilized to measure important coating plasma parameters. Putting the Langmuir electrode to the same coating conditions as the charge will offer information of the progress of the PACVD process. The use of the sensor should especially show events or conditions which conduct to local or generally bad technological coating properties. So in the early stages of coating development the quality can be recognized and possibly corrected or avoided by variation of the process parameters. Sensor controled processing of PACVD-technic will lead to better coating quality and will increase the reproduceability.     

Mixed oxide coatings for optics

Material mixtures offer new possibilities for synthesizing coating materials with tailored optical and mechanical properties. We present experimental results on mixtures of HfO2, ZrO2, and Al2O3, pursuing applications in UV coating technology, while the mixtures are prepared by magnetron sputtering, ion beam sputtering, plasma ion-assisted deposition (PIAD), and electron beam evaporation without assistance. The properties investigated include the refractive index, optical gap, thermal shift, and mechanical stress. The first high reflectors for UV applications have been deposited by PIAD.     

氧化铪薄膜的制备及其性能研究

采用电子束反应蒸发金属铪、APS离子辅助反应蒸发氧化铪、RF离子辅助反应蒸发氧化铪三种方式制备了单层HfO2薄膜,对样品的光学性能、结构特性以及抗激光损伤特性进行研究,结果表明,离子辅助使氧化铪薄膜更为致密;电子束蒸发氧化铪薄膜为非晶态,离子辅助制备氧化铪薄膜为晶态。选择合适的离子辅助工艺,有利于降低薄膜的缺陷吸收,提高氧化铪薄膜的抗损伤性能。