磁控溅射膜厚均匀性与靶-基距关系的研究

从理论上分析了平面磁控溅射靶沉积薄膜的厚度均匀性.根据磁控溅射阴极靶刻蚀的实际测量数据,建立了靶的刻蚀速率方程,以此为依据,对膜厚均匀性的有关公式进行了讨论.采用计算机计算了基片处于不同靶-基距时,膜厚均匀性的分布.研究结果表明,随着靶基距的增加,膜厚均匀性逐渐变好.在同样的靶基距下,沿靶长度方向的均匀性明显优于宽度方向.最后,通过实验证实了上述结论.     

脉冲激光沉积Ti50Ni36Cu14薄膜的成分均匀性

采用脉冲激光沉积(PLD)技术制备了Ti50Ni36Cu14合金薄膜.研究表明,PLD合金薄膜的成分与沉积距离(基片/靶间距)、激光脉冲频率有较大关系.当沉积距离(D)为20～30mm时,可获得成分均匀稳定的合金薄膜;当其它条件相同,激光脉冲频率(F)为5Hz时,合金薄膜与靶成分更为接近.采用PLD技术制备的Ti50Ni36Cu14合金薄膜成分均匀性较好,同时与磁控溅射薄膜相比PLD薄膜的平均成分更加接近靶体.采用本工艺获得的Ti50Ni36Cu14薄膜的平均成分为47.53at.%Ti、38.90 at.% Ni和13.57 at.%Cu.     

直流磁控溅射中Ar气压强对TbFeCo磁光薄膜均匀性的影响

本文研究了磁光盘生产中 Ar气压强对直流磁控溅射 Tb Fe Co磁光薄膜均匀性的影响 ,通过调整溅射气压来提高薄膜的厚度均匀性和成分均匀性。在靶 -基片距离为 6 0 0 m m,溅射功率为 6 0 0 W,溅射气压为 0 .6～0 .8Pa的条件下 ,获得了均匀性良好的磁光薄膜 ,并将此工艺参数用于磁光盘的生产     

靶基距对脉冲激光沉积β-FeSi2薄膜质量的影响

常用的分子束外延、粒子束沉积法难以获得均匀、致密性好的单一相β-FeSi2薄膜,利用脉冲激光沉积及热退火处理法在P型Si(100)基片上制备了均匀的单一相β-FeSi2薄膜。利用X射线衍射仪、扫描电镜、原子力显微镜及红外光谱仪研究了靶基距对β-FeSi2薄膜的结构、组分、结晶质量、表面形貌及光吸收特性的影响。结果表明:随着靶基距的增加,薄膜的晶化程度先变差后增强再变差,晶粒尺寸先减小后增大再减小,颗粒分布均匀性先变好后变差;表面粗糙度先减小后增大;靶基距为40 mm时,β-FeSi2薄膜的结晶度较高,颗粒大小均匀、趋于球形化,薄膜致密性较好,粗糙度较低,对红外光的吸收较好。     

小圆形平面靶倾斜磁控溅射镀膜均匀性研究

基于小圆形平面靶倾斜磁控溅射的实际情况,针对靶材环形刻蚀槽与水平工件台存在夹角的特点,建立数学模型。利用MATLAB软件进行模拟仿真,研究靶材与工件台正对且高度固定时,不同夹角对膜厚分布的影响。我们发现在工件台相对靶材的水平距离上,膜厚先增加后降低。当靶材夹角适当时,在工件台固定的区域范围内,薄膜沉积速率的变化近似直线。根据薄膜厚度在工件台水平面呈圆弧状递减分布实际特点,模拟出在4英寸的衬底上片内均匀性。根据模拟结果,我们在4英寸的衬底上制备出片内非均匀性小于0.6%的氮化钽薄膜,验证了数学模型的合理性,并解释了非均匀性的实验结果优于模拟计算结果的原因。这为设计制造磁控溅射镀膜设备提供了参考。     

大面积VHF-PECVD用多点馈入平行板电极馈入点优化的数值研究

本文采用二维准平面电路模型,对大面积甚高频等离子体增强化学气相沉积（VHF-PECVD）用多点馈入平行板电极馈入点的优化进行了数值研究,讨论了不同的多点馈入模式对平行板电极间真空电势分布均匀性的影响。研究结果表明：对于给定激发频率和尺度的大面积平行板电极,功率馈入连接点位置分布和数量成为影响电极间电势分布均匀性的两个重要可控参量,通过优化功率馈入连接点数量和连接点位置分布,可以抑制电势驻波效应及功率馈入点对数奇点效应,很大程度上有效地改善了电极间电势分布的均匀性。本文数值计算结果在一定程度上为VHF-PECVD技术用平行板电极实现大面积薄膜均匀沉积的系统设计提供了理论指导。     

小圆平面靶磁控溅射镀膜均匀性研究

本文从圆平面靶磁控溅射的原理出发,针对圆形平面靶面积小于基片面积的特点进行分析,建立膜厚分布的数学模型,并利用计算机进行模拟计算,目的在于探寻平面靶材面积小于基片面积时影响膜厚均匀性的因素。模拟计算的结果表明:基片偏心自转时,靶基距和偏心距对膜厚分布均有影响。偏心距一定时,随着靶基距的增大,薄膜厚度变小,膜厚均匀性有提高的趋势;靶基距一定时,随着偏心距的增大,膜厚均匀性先变好后变差。当基片自转复合公转时,随着转速比的增大,膜厚均匀性逐渐变好,转速比增大到一定程度后,它对膜厚均匀性的影响逐渐变小。圆形平面靶的刻蚀环范围的变化对薄膜的均匀性有一定的影响。这些理论为小圆平面磁控溅射系统的设计和实际应用提供了理论依据。     

磁控溅射制备紧固件防咬死涂层的厚度均匀性研究

为了研究磁约束聚变装置支撑装置紧固件的螺母和螺栓表面防咬死涂层的均匀性,利用磁控溅射技术在管形器件的内表面和外表面制备了铜膜,应用台阶仪进行薄膜厚度测试。采用矩形铜板作为磁控溅射靶,采用单自转和公转加自转两种方式进行沉积,分析了铜膜在管形器件的内表面和外表面的膜厚分布规律。结果表明:无论螺母还是螺栓,公转加自转相对于单自转制备薄膜的均匀性都更好,随着孔(管)径的变小薄膜厚度变大。     

考虑受拉薄膜效应的板块平衡法修正及在混凝土双向板中的应用

经典塑性铰线理论中的板块平衡法无法考虑钢筋混凝土板在大变形时产生的受拉薄膜效应的影响。为解决这一问题,该文提出了一种可以考虑受拉薄膜效应的修正板块平衡法。该方法将钢筋混凝土板的受力行为分为屈服前和屈服后两个阶段。假设钢筋混凝土板在屈服前的变形为弹性,分别采用Navier法和板块平衡法确定板的屈服挠度和屈服承载力。为考虑屈服后钢筋混凝土板中产生的受拉薄膜效应,假设板底塑性铰线截面上钢筋的竖向分力为产生受拉薄膜效应的主要原因,而钢筋的水平分力则与截面上混凝土的压力组成力偶构成了钢筋混凝土板的截面抵抗弯矩。通过上述修正,可以获得由考虑受拉薄膜效应的修正板块平衡法计算的钢筋混凝土板的全过程荷载-挠度曲线。为验证该文方法,对大挠度足尺混凝土双向板进行了应用研究。通过对比可知,理论分析结果与试验结果较为接近,从而验证了修正板块平衡法的有效性。     

直流磁控射中Ａr气压强对ＴbFeCo磁光薄膜均匀性的影响

本文研究了磁光盘生产中Ａr气压对直流磁控溅射ＴbFeCo磁光萍膜均匀性的影响,通过调整溅射气压来提高薄膜的厚度均习性和成分均匀性,在靶－基片距离为600mm,溅射功率为６００Ｗ,溅射气压为０．６~0.8Ｐa的条件下,获得了均匀性良好的磁光薄膜,并将此工艺参数用于磁光盘的生产。     

离轴溅射法中最佳几何参量的预测

为提高磁控溅射薄膜的厚度均匀性,采用理论计算的方法分析了离轴溅射薄膜的厚度分布,结果表明最佳偏心距及对应的有效薄膜尺寸都与靶基距呈线性增大的关系。溅射原子的角分布、溅射环的宽度以及膜厚均匀性要求都会影响该线性关系。针对以上变化因子,本文归纳出了普适的公式,可方便地对实际工作进行指导。     

多层微纳薄膜的高精度检测技术进展

在半导体、机械加工等行业中广泛应用的多层微纳薄膜通常是由数个纳米厚度的单层膜叠加形成的,在其制造过程中,由于工艺条件所限,薄膜厚度的均匀性会出现误差,进而影响其性能。因此薄膜厚度的准确测量至关重要,亟需一种无损、高精度、快速的检测技术对薄膜的厚度及其均匀性进行测量、检测。回顾近年来多层膜在不同领域的应用现状,分析了目前应用于多层膜厚度测量的技术（如X射线衍射等）及其不足,以及椭圆偏振法技术的研究进展,最后介绍了机器学习在厚度测量中的应用,并对未来机器学习与测量结合的前景进行了展望。     

The effects of film thickness variations on the residual stress distributions in coated Cr thin films

Generally, the residual stress of thin film coatings is calculated using Stoney's equation. However, variables in the manufacturing of the coated film, such as crystalline particle size and the unevenness of the thickness of the film, cause the radius of curvature of the beam to vary all over the beam. The cantilever beam curves not only in the axial direction but also in the transverse direction. Therefore, the residual stress in a film coating comprises not only axial residual stress but also transverse residual stress, and its distribution is also not uniform. Under such conditions, Stoney's equation must be modified. In this study, Si was used as a substrate in the production of cantilever beam specimens. Chromium thin films of various thicknesses were coated onto the Si substrates. The 3D digital image correlation technique was used to measure the out‐of‐plane displacement of the specimens at various positions. Then the modified Stoney's equation was used to obtain the axial and transverse residual stress at each measurement point to study the effect of variations in the thickness of the thin film on the magnitude and uniformity of the distribution of the residual stresses. Three thin film thicknesses 1, 2, and 3 μm were studied, and three specimens for each thickness were used. For each specimen, axial and transverse residual stresses were obtained at nine test points, and the equivalent residual stress was calculated. The results of this study reveal that as the difference between the thicknesses of the coating increased, average equivalent residual stress decreased and the distribution of stresses became more uniform. By comparing the corresponding results for the 1‐ and 3‐μm‐thick films revealed that the confidence levels in the average value and uniformity of the equivalent residual stress distribution, which increased with thickness, were 92.81% and 80.57%, respectively.     

倒圆锥面基底蒸发镀膜均匀性理论分析

通过计算得出了蒸发源位于倒圆锥面正下方外部镀膜时锥面上各点的膜厚方程,并对整个锥面上膜厚均匀性进行了理论分析。结果表明：当圆锥面形状固定时,蒸发源与圆锥底圆圆心距离增大使锥面上膜厚均匀性变好;当蒸发源固定时,增大底圆半径导致锥面上膜厚均匀性变差。在同样的配置下,蒸发源为点源或小平面源时锥面上膜厚均匀性的变化趋势一致,小平面源蒸镀比点源蒸镀时圆锥面上膜厚均匀性差。     

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。     

Characterization of ultrathin SOI film and application to short channel MOSFETs

In this study, a very dilute solution (NH(4)OH:H(2)O(2):H(2)O 1:8:64 mixture) was employed to reduce the thickness of commercially available SOI wafers down to 3?nm. The etch rate is precisely controlled at 0.11???s(-1) based on the self-limited etching speed of the solution. The thickness uniformity of the thin film, evaluated by spectroscopic ellipsometry and by high-resolution x-ray reflectivity, remains constant through the thinning process. Moreover, the film roughness, analyzed by atomic force microscopy, slightly improves during the thinning process. The residual stress in the thin film is much smaller than that obtained by sacrificial oxidation. Mobility, measured by means of a bridge-type Hall bar on 15?nm film, is not significantly reduced compared to the value of bulk silicon. Finally, the thinned SOI wafers were used to fabricate Schottky-barrier metal-oxide-semiconductor field-effect transistors with a gate length down to 30?nm, featuring state-of-the-art current drive performance.     

Simulation of the organic thin film thickness distribution for multi-source thermal evaporation process

A model of multi-source thermal evaporation process was proposed to achieve higher deposition rate and uniformity of organic thin film. In this model, several point type sources were uniformly distributed around a circle and evaporated simultaneously to form a surface-like source. Based on the Monte Carlo method, the evaporation process was simulated, and the effect of the number of point type sources, circle radius and source-substrate distance on the uniformity was analyzed. Based on the method proposed in this paper, the uniformity of the thickness in the organic layer was successfully controlled in 5%.     

Optical-constant calculation of non-uniform thickness thin films of the Ge10As15Se75 chalcogenide glassy alloy in the sub-band-gap region (0.1–1.8 eV)

Optical-transmission spectra are very sensitive to inhomogeneities in thin films. In particular, a non-uniform thickness produces a clear shrinking in the transmission spectrum at normal incidence. If this deformation is not taken into account, it may lead to serious errors in the calculated values of the refractive index and film thickness. In this paper, a method first applied by Swanepoel for enabling the transformation of an optical-transmission spectrum of a thin film of wedge-shaped thickness into the spectrum of a uniform film, whose thickness is equal to the average thickness of the non-uniform layer, has been employed. This leads subsequently to the accurate derivation of the refractive index in the subgap region (0.1–1.8 eV), the average thickness, as well as a parameter indicating the degree of film-thickness uniformity. This optical procedure is applied to the particular case of freshly-prepared films of the Ge₁₀As₁₅Se₇₅ ternary chalcogenide glassy alloy. The dispersion of the refractive index is discussed in terms of the Wemple–DiDomenico single-oscillator model. The optical-absorption edge is described using the ‘non-direct transition' model proposed by Tauc, and the optical energy gap is calculated by Tauc's extrapolation. Finally, the photo-induced and thermally induced changes in the optical properties of the a-Ge₁₀As₁₅Se₇₅ layers are also studied.     

Synthesis of copper nanoparticles by solid-state plasma-induced dewetting

Copper nanoparticles were prepared by the plasma treatment of Cu thin films without extra heating. The Cu nanoparticles were formed through a solid-state dewetting process at temperatures of less than 450 K. The particle sizes, from 10 to 80 nm, were controlled by changing the thickness of the Cu film; the particle size increased linearly with the film thickness. The Cu nanoparticles produced by plasma treatment showed an excellent size uniformity compared to those prepared by heat treatment. In the early stage of the dewetting of the Cu film, uniformly distributed holes nucleated, and the holes grew and coalesced until the Cu nanoparticles were formed. The low operating temperatures used contributed to the production of uniform Cu nanoparticles.     

Solution-Processed Centimeter-Scale Highly Aligned Organic Crystalline Arrays for High-Performance Organic Field-Effect Transistors

Solution-printed organic single-crystalline films hold great potential for achieving low-cost manufacturing of large-area and flexible electronics. For practical applications, organic field-effect transistor arrays must exhibit high performance and small device-to-device variation. However, scalable fabrication of highly aligned organic crystalline arrays is rather difficult due to the lack of control over the crystallographic orientation, crystal uniformity, and thickness. Here, a facile solution-printing method to fabricate centimeter-sized highly aligned organic crystalline arrays with a thickness of a few molecular layers is reported. In this study, the solution shearing technique is used to produce large-area, organic highly crystalline thin films. Water-soluble ink is printed on the hydrophobic surface of organic crystalline films, to selectively protect it, followed by etching. It is shown that the addition of a surfactant dramatically changes the fluid drying dynamics and increases the contact line friction of the aqueous solution to the underlying nonwetting organic crystalline film. As a result, centimeter-scale highly aligned organic crystalline arrays are successfully prepared on different substrates. The devices based on organic crystalline arrays show good performance and uniformity. This study demonstrates that solution printing is close to industrial application and also expands its applicability to various printed flexible electronics.