化学气相沉积钨铼合金工艺研究

以ReF6、WF6及H2为原料，用化学气相沉积法，成功地在铜基体表面沉积出钨铼合金。试验分析表明：合金成分均匀，且可由反应气体配比控制，随ReF6增加，合金中铼含量增加；沉积层组织和形貌随沉积温度升高或反应气体中ReF6的增加，由致密的柱状晶发展为杂乱的树枝晶；沉积层结构随ReF6的增加由单一固溶体向固溶体＋金属间化合物＋铼单质发展。     

沉积温度对化学气相沉积铼涂层性能的影响

利用五氯化铼热分解反应,采用冷壁式现场氯化化学气相法在钼基体沉积铼涂层,分析不同沉积温度对铼涂层的物相组成、沉积规律、表面形貌、密度和硬度的影响。实验结果表明:沉积所得均为纯铼涂层,晶粒生长方向均以(002)晶面为主;随着沉积温度的上升,铼涂层的沉积速率和沉积效率大幅提升,表面形貌由复杂多面体态变为六棱锥状;涂层组织致密,相对密度最高可达99.9%,维氏硬度随沉积温度升高而升高,最高达6100 MPa。     

化学气相沉积法制备难熔金属的研究现状与前景

难熔金属材料以其熔点高、高温性能好和耐腐蚀性优异等特点被广泛应用于航空航天、化学化工和国防军工等领域。化学气相沉积法是目前获得高纯致密、尺寸精确的难熔金属制品的最佳手段。本文介绍了钨、钼、钽、铌和铼五种难熔金属元素的应用领域,综述了采用不同的化学气相沉积法制备难熔金属及其合金的工艺、制品性能和具体用途,总结了金属源先驱体类型对化学气相沉积工艺的影响,分析展望了化学气相沉积法在制备难熔金属上的应用前景。     

生产铼部件的电子束物理气相沉积法

难熔金属铼是高温结构件和能源装置用的理想材料,如太阳能火箭发动机、热交换器、航天和导弹推进装置。它的优异耐蚀性能使它适用于高温火箭发动机和热气阀。铼有很高的熔点,仅次于钨,铼在高温下有最大的拉伸强度和蠕变断裂强度。因此,铼已被美国国防部的航天与导弹计划选用,用来制造导弹部件,包括推进器、调节阀管、供气管、拉杆、涂铼的球形件。然而由于铼冷加工硬化,每次加工变形5%～10%就需要完全再结晶退火。另外采用粉末冶金(PM)和化学气相沉积(CVD)很难制备铼部件。因为粉末冶金技术对于难熔金属的部件成形,遇到的困难很多,CVD方…     

化学气相沉积

化学气相沉积(Chemical Vapor Deposition,简称CVD)是利用化学反应由气相生长固体物质的方法。一般把反应物是气体而生成物之一是固体的反应称为CVD反应。通常CVD要利用高温或其它激活方法,依靠化学反应制取所需要的薄厚膜。     

采用CVD法还原挥发性铼的氧化物制备超细铼粉(英文)

研究了一种以高铼酸铵为原料,采用化学气相沉积(CVD)制备超细铼粉的新方法。通过控制氧分压,使得NH4ReO7分解为具有挥发性的ReO4、Re2O7,再采用载气将其输运至还原区,经氢气还原生成超细铼粉。热力学计算表明,在NH4ReO7分解过程中,控制氧分压高于101.248Pa时,Re2O7将不会分解为低价氧化物,DSCTGA分析结果也证实了这一点。采用该方法制备的铼粉,粒度为100~800nm,D50为308nm,比表面积为4.37m2/g,氧含量为0.45%。     

贵金属化学气相沉积的研究进展

简要介绍了贵金属薄膜和涂层材料化学气相沉积(CVD)技术的研究进展,包括贵金属的CVD制备方法、沉积贵金属的各种前驱体化合物以及CVD制备的贵金属薄膜和涂层的应用状况等。     

Properties of chemically vapor deposited blanket tungsten films on tin glue layers prepared by chemical vapor deposition

The dependence of CVD W growth on various types of TiN layers was investigated with blanket and patterned wafers. There were no appreciable effects of the properties of TiN on the resistivity, structure, growth rate or reflectivity of CVD W in the case of blanket wafers; however, the stress of the W layer was found to be dependent upon the type of TiN glue layer adopted. W deposited on the TDMAT-TiN glue layer exhibits the lowest stress levels among the tested TiN films. TiCl₄-TiN proved to be superior to TDMAT-TiN from the viewpoint of W conformality. Although there was no appreciable effect of deposition temperature silane reduction time, contact size or shape of contact upon the W conformality on a TiCl₄-TiN layer, the W conformality on TDMAT-TiN was highly dependent on the above parameters, apparently caused by insufficiently plasma treated TiN on the side walls of contacts.     

Effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition

The effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition are investigated. The deposition parameters are selected as follows. The CH₄/(CH₄ + N₂) ratio is in the range between 20% and 100%; the temperature is set from 1173 to 1248 K; the working pressure is arranged between 50 and 100 kPa, and the residence time is ranging from 1.47 to 7.37 s. The deposition rate, microstructure, and electrical resistivity of carbon coatings are measured. The low-temperature surface morphology of carbon-coated optical fibers is elucidated. Experimental results indicate that the deposition rate increases with increasing the CH₄/(CH₄ + N₂) ratio, deposition temperature, working pressure, and residence time. The activation energy (= 456 kJ/mol) of carbon deposition from methane was shown to correlate to the activation energy of methane dissociation. The deposition rate is proportional to about first-order of partial pressure of methane, and thus, the deposition process is mainly controlled by the process to create mono-carbon species in the carbon film. As the deposition rate increases, the size and number of particles on the carbon coating surface and electrical resistivity of carbon coatings increase, while the ordered degree, nano-crystallite size, and sp² carbon atoms of the carbon coatings decrease. Additionally, the low-temperature surface morphology of carbon coatings shows that as the carbon coating thickness is large enough to sustain the thermal loading, decreasing the deposition rate is good for producing hermetic optical fiber coatings.     

石墨表面化学气相沉积SiC及C涂层的制备

以C3H8和CH3SiCl3（MTS）为先驱体原料,用化学气相沉积法在石墨基体表面分别制备了C涂层、SiC涂层。采用X射线衍射仪和扫描电镜分析了两种涂层的成分和表面微观形貌,研究了温度和气体流量对涂层微观形貌的影响。结果表明,当C3H8＋N2流量为140 L/h,沉积温度为1300℃时,石墨基体表面可获得致密度较高的C涂层,而且涂层比较平整、均匀,而流量为160 L/h时涂层比较粗糙。当MTS＋H2流量为60 L/h、沉积温度1100℃时在石墨基体表面可以形成致密的SiC涂层,1300℃时生长的SiC晶体形貌发生改变,涂层厚度增加,表面有较多圆形凸起。当MTS-H2气体流量增大可使SiC涂层晶粒尺寸增大,但大流量易产生涂层剥落。采用C和SiC共沉积涂层作过渡层,涂层与石墨基体界面结合增强;SiC涂层与石墨基体之间存在厚度较大的过渡区域,过渡区域平均厚度约2μm。     

固态输送ZrCl4低压化学气相沉积制备ZrC涂层的特征

采用ZrCl4-CH4-H2-Ar反应体系、固态输送ZrCl4粉末低压化学气相沉积(CVD)制备ZrC涂层。研究温度对低压化学气相沉积ZrC涂层物相组成、晶体择优生长、涂层表面形貌、断面结构、涂层生长速度和沉积均匀性等方面的影响。结果表明:不同温度下沉积的涂层主要由ZrC和C相组成;随着温度的升高,ZrC晶粒(200)晶面择优生长增强,颗粒直径增大,表面致密性增加,沉积速率上升;涂层断面结构以柱状晶为主;随着离进料口距离的增加,涂层的沉积速率逐渐减小;1 500℃时,沉积系统的均匀性比1 450℃时的差。     

烧结作用对CVD法超细铼粉性能的影响

研究了一种化学气相沉积(CVD)制备超细铼粉的新方法,即以NH4ReO7为原料,通过将其分解为Re2O7后气相输运至还原区,经氢气还原生成超细铼粉.对不同还原温度下制备的超细铼粉样品,采用XRD、SEM、激光粒度分析进行表征,实验揭示了烧结作用对晶粒尺寸、形貌、表面状态及粒度等粉末性能的影响规律.结果表明,随还原温度升高,烧结作用增强,制备的超细铼粉晶粒尺寸增大,具有更好的球形度,表面趋于光洁,平均粒径增大.     

硅掺杂CVD金刚石薄膜

研究硅掺杂对CVD金刚石薄膜形貌、结构特性和成分的影响。通过向丙酮中加入正硅酸乙酯作为反应气体,在硅基底上沉积硅掺杂CVD金刚石薄膜。金刚石薄膜的表面形貌和显微组织由场发射电镜表征。金刚石薄膜的成分通过拉曼光谱和X射线衍射（XRD）进行研究。薄膜的表面粗糙度由表面轮廓仪评估。结果表明,硅掺杂会降低晶粒尺寸,促进晶粒细化并抑制三角锥形形貌。XRD研究表明,（111）朝向的晶面显著减少。拉曼光谱研究表明,硅掺杂会促进薄膜中硅碳键的形成以及非金刚石相的增多。在硅碳浓度比为1％时,沉积得到光滑的细晶粒金刚石薄膜。     

Time-modulated chemical vapor deposition of diamond films

This article investigates the role of substrate temperature in the deposition of diamond films using a newly developed time-modulated chemical vapor deposition (TMCVD) process. TMCVD was used to deposit polycrystalline diamond coatings onto silicon substrates using hot-filament chemical vapor deposition system. In this investigation, the effect of (a) substrate temperature and (b) methane (CH₄) content in the reactor on diamond film deposition was studied. The distinctive feature of the TMCVD process is that it time-modulates CH₄ flow into the reactor during the complete growth process. It was noted that the substrate temperature fluctuated during the CH₄ modulations, and this significantly affected some key properties of the deposited films. Two sets of samples have been prepared, in each of which there was one sample that was prepared while the substrate temperature fluctuated and the other sample, which was deposited while maintaining the substrate temperature, was fixed. To keep the substrate temperature constant, the filament power was varied accordingly. In this article, the findings are discussed in terms of the CH₄ content in the reactor and the substrate temperature. It was found that secondary nucleation occurred during the high timed CH₄ modulations. The as-deposited films were characterized for morphology, diamond-C phase purity, hardness, and surface roughness using scanning electron microscopy, Raman spectroscopy, Vickers hardness testing, and surface profilometry, respectively.     

氮气对DC-PCVD法制备金刚石薄膜影响的研究

采用直流热阴极等离子体化学气相沉积方法,用甲烷、氢气、氮气的混合气体在Mo基底上成功制备了金刚石薄膜.分别采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)对不同流量氮气氛下生长金刚石薄膜的形貌、取向、质量进行了表征.结果表明:适量氮气的加入,不仅可以促进金刚石薄膜的生长速率,还可以促进金刚...     

Growth of N-polar GaN on vicinal sapphire substrate by metal organic chemical vapor deposition

The growth and properties of N-polar Ga N layers by metal organic chemical vapor deposition(MOCVD) were reported. It is found that N-polar Ga N grown on normal sapphire substrate shows hexagonal hillock surface morphology. With the misorientation angles increasing from 0.5° to 2.0° toward the a-plane of the sapphire substrate, the number of the hillock becomes less and less and finally the surface becomes flat one on the sapphire substrate with the misorientation angle of 2°. It is also found that the crystalline quality and the strain in the Ga N are greatly influenced by the misorientation angle.