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利用大面积硅片制作X射线光栅和硅基微通道板等都涉及硅的热氧化工艺。热氧化使具有高深宽比微结构的大面积硅片产生形变,严重影响了这些器件的应用。本文以5英寸硅片为例,研究了硅基微结构在热氧化过程中的变形问题,定性分析了产生形变的力学因素,提出了减小形变的氧化方法。首先实验制作了具有高深宽比微结构的硅片,采用不同的氧化方法,比较了变形的大小。结果表明,通过控制热氧化过程中的温度来控制热膨胀系数和在热氧化过程中施加外部热塑应力等方法能够有效地减小热氧化变形量。 相似文献
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等离子体低温刻蚀是一种针对高深宽比结构的干法刻蚀技术。本文在低温刻蚀单晶硅样品时得到典型的刻蚀结果为:各向异性值>0.99,硅刻蚀速率>1.5μm/min,对SiO2刻蚀选择比>75,说明该刻蚀方法很具竞争力。通过对载片台温度、反应气体配比、腔体气压和ICP线圈功率等工艺参数的系列实验分析,证明低温刻蚀高深宽比硅微结构必需一定的低温和氧,同时揭示出低温刻蚀过程的主要控制因素是离子轰击而非刻蚀表面的化学反应。本文还对刻蚀过程中刻蚀滞后和凹蚀现象的产生机理进行了分析讨论,指出介电质掩蔽层的充放电效应导致了凹蚀,而刻蚀滞后的诱因则与通常的刻蚀情况不同,主要是台阶对离子轰击的覆盖效应。 相似文献
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多层等离子体蚀刻技术的研究 总被引:3,自引:0,他引:3
干法刻蚀现已成为微小高深宽比结构加工与微细图形制作的重要手段.提出了一种新的干法刻蚀技术一多层等离子体蚀刻,充分利用腔体的空间布局,布置多层电极,并采用分层送气装置输送放电气体,实现多层同时进行刻蚀,可成倍提高产能.采用该技术刻蚀光阻为例,从空间与时间两个角度分析了工艺参数对刻蚀速率与均匀性的影响规律与作用机理.实验结果表明,极板间距为50/55/60mm(由下向上),工作压力为40Pa,R[O2:Ar]为1/2,RF功率为600W时,整炉次刻蚀速率均值为14.395nm/min,均匀性为9.8%,此时工艺最为合理. 相似文献
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对PMMA进行反应离子深刻蚀以获得高深度比微结构.研究了纯氧刻蚀气体中加入CHF3对刻蚀速率、图形形貌等的影响.纯氧刻蚀PMMA,钻蚀现象严重.加入CHF3后,刻蚀速率随CHF3含量增加而下降.加入适量CHF3,可以在侧壁形成钝化层,保护侧壁不受钻蚀.当CHF3含量为40%,刻蚀功率30 W,工作气压为4 Pa时,即使刻蚀深度达到400 μm,侧壁仍然陡直,刻蚀深宽比大于10. 相似文献
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A factor responsible for the appearance of a dome-shaped front of macropore etching in thin silicon wafers during their photoelectrochemical etching in a cell with a ring anode has been established. It is shown that the formation of a dome-shaped front is related to a radial voltage drop in the substrate, which leads to a decrease in the current density in the central part of the etched wafer. The effect of applied voltage on the shape of the front has been studied. We suggest monitoring of the development of nonuniformity in the course of etching using a change (i) in the temporal variation of the adjusted intensity of illumination and (ii) in the current-voltage characteristic. Various methods intended to provide deep uniform macropores are considered. 相似文献
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基于多掩膜光刻工艺的MEMS体硅加工 总被引:2,自引:0,他引:2
本文提出了一种新颖的MEMS多掩膜工艺,实现了带有大台阶和大深宽比窄槽的衬底上的体硅精细加工。通过薄胶多次光刻在衬底上制作出氧化硅(SiO2)、氮化硅(Si3N4)、光刻胶(photo-resist,PR)等材料的多层掩膜图形,每层掩膜可以进行一次衬底刻蚀或腐蚀,刻蚀或腐蚀完毕后去除该层掩膜。该工艺解决了MEMS工艺中的深坑涂胶和光刻问题,结合深反应离子刻蚀(Deep Re-active Ion Etching,DR IE)、湿法腐蚀等工艺可以用于多级台阶、深坑底部精细结构、微结构释放等MEMS工艺。 相似文献
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A way of achieving lightly doped emitter is a combination of a heavy emitter diffusion and emitter etch back, which has an added advantage of phosphorous diffusion gettering. However, this chemical emitter etch-back process must fulfil some critical requirements, e.g. cost-effectiveness, near-conformal Si etching even after deep emitter etch back, controlled Si etch rate, post-etch clean Si surface and lowest safety issues in chemical handling and drainage. In this work, we report a new low-cost (less than 1 US Cents/wafer), single-chemical, non-acidic, high-throughput emitter etch-back process for tube-diffused emitters for crystalline Si wafers. This process uses only sodium hypochlorite solution at 80 °C as the Si etchant. This process is versatile with its applications on phosphorous and boron tube-diffused monocrystalline Si and phosphorous tube-diffused multicrystalline Si wafers. The preparation, usage and drainage of this highly diluted solution are easy and safe. The Si etching process leads to excellent spatial uniformity over large-area Si wafers (243 cm2). With deep etch back resulting in a change of sheet resistance by ~60 Ω/sq, the standard deviation value changes by only 2.7%. High surface conformity in the etch-back surface is evident from reflectance studies. Quasi-steady-state photoconductance and photoluminescence imaging are used to demonstrate improved electrical parameters of the etch-back wafers. 相似文献
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Junghun Chae 《Materials Letters》2009,63(21):1823-1825
Large-area patterning of carbon nanotubes (CNTs) using a nonlithographic process is demonstrated. Projection imaging with deep ultraviolet radiation from 248 nm KrF excimer laser and material-assisted photoablation were used to pattern the CNTs. A matrix of CNTs dissolved in a DMF solution was deposited on a silicon wafer by spin coating, followed by coating of photodefinable polyimide on the CNTs. The CNTs and the polyimide layer were simultaneously patterned by the excimer laser projection photoablation process. Even though CNTs cannot be directly photoablated by low-fluence excimer laser radiation, simultaneous patterning of the illuminated CNT-polyimide combination region occurred due to the physical force of dissociated fragments of polyimide layer. We have demonstrated clean, large-area patterning of CNTs on 100 mm diameter Si wafers. Additionally, this patterning process is economical and provides higher throughput compared with conventional methods. 相似文献
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Lisker M Marschmeyer S Kaynak M Tekin I 《Journal of nanoscience and nanotechnology》2011,11(9):8061-8067
The formation of a Through Silicon Via (TSV) includes a deep Si trench etching and the formation of an insulating layer along the high-aspect-ratio trench and the filling of a conductive material into the via hole. The isolation of the filling conductor from the silicon substrate becomes more important for higher frequencies due to the high coupling of the signal to the silicon. The importance of the oxide thickness on the via wall isolation can be verified using electromagnetic field simulators. To satisfy the needs on the Silicon dioxide deposition, a sub-atmospheric chemical vapor deposition (SA-CVD) process has been developed to deposit an isolation oxide to the walls of deep silicon trenches. The technique provides excellent step coverage of the 100 microm depth silicon trenches with the high aspect ratio of 20 and more. The developed technique allows covering the deep silicon trenches by oxide and makes the high isolation of TSVs from silicon substrate feasible which is the key factor for the performance of TSVs for mm-wave 3D packaging. 相似文献
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Nayfeh M.H. Satish Rao Nayfeh O.M. Smith A. Therrien J. 《Nanotechnology, IEEE Transactions on》2005,4(6):660-668
We constructed ultraviolet (UV) photodetectors using thin films of silicon nanoparticles as active media. The Si nanoparticle films are electrodeposited at room temperature on Si p-type substrates. Uniform silicon nanoparticles of 1-nm diameter are dispersed from Si wafers using electrochemical etching. The nanoparticles are ultrabright under UV excitation, with nanosecond luminescence time characteristics. Current-voltage (I--V) characteristics indicate a photoconductor in series with a diode-like junction with a large enhancement in the forward current under UV illumination. Our results point to a sensitive UV detector with good visible blindness where the particle films effectively constitutes a wide-bandgap material. 相似文献
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Liu Y Lai T Li H Wang Y Mei Z Liang H Li Z Zhang F Wang W Kuznetsov AY Du X 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(9):1392-1397
Nanoscale textured silicon and its passivation are explored by simple low-cost metal-assisted chemical etching and thermal oxidation, and large-area black silicon was fabricated both on single-crystalline Si and multicrystalline Si for solar cell applications. When the Si surface was etched by HF/AgNO(3) solution for 4 or 5 min, nanopores formed in the Si surface, 50-100 nm in diameter and 200-300 nm deep. The nanoscale textured silicon surface turns into an effective medium with a gradually varying refractive index, which leads to the low reflectivity and black appearance of the samples. Mean reflectance was reduced to as low as 2% for crystalline Si and 4% for multicrystalline Si from 300 to 1000 nm, with no antireflective (AR) coating. A black-etched multicrystalline-Si of 156 mm × 156 mm was used to fabricate a primary solar cell with no surface passivation or AR coating. Its conversion efficiency (η) was 11.5%. The cell conversion efficiency was increased greatly by using surface passivation process, which proved very useful in suppressing excess carrier recombination on the nanostructured surface. Finally, a black m-Si cell with efficiency of 15.8% was achieved by using SiO(2) and SiN(X) bilayer passivation structure, indicating that passivation plays a key role in large-scale manufacture of black silicon solar cells. 相似文献
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E. Gómez-Barojas O. López-Hernández F. Flores-Gracia J. Tepal-Prisco R. Silva-González E. Sánchez-Mora 《Journal of Superconductivity and Novel Magnetism》2013,26(6):2219-2222
Porous silicon layers have been prepared from non-polished p-type silicon wafers of (100) orientation. Scanning electron microscopy and fluorescence spectroscopy have been used to characterize the morphological and optical properties of porous silicon. The influence of varying the anodizing current density on the morphological and optical properties of porous silicon has been investigated. SEM micrographs show that by increasing the anodizing current density in the electrochemical process two peculiar surface morphologies are obtained. The surface morphology in the central region of the sample consists of solid cells delimited by trenches and the trenches bottom is covered by polyhedral pores, and the surface morphology in the periphery contains polyhedral and current-line-oriented pores. The fluorescence spectrum peak at the anodizing current density of 93 mA/cm2 gets the maximum intensity and is blue shifted. 相似文献