Pulsed metal organic chemical vapor deposition of InAlN-based heterostructures and its application in electronic devices

As a promising group III-nitride semiconductor material, InAlN ternary alloy has been attracted increasing interest and widespread research efforts for optoelectronic and electronic applications in the last 5 years. Following a literature survey of current status and progress of InAlN- related studies, this paper provides a brief review of some recent developments in InAlN-related III-nitride research in Xidian University, which focuses on innovation of the material growth approach and device structure for electronic applications. A novel pulsed metal organic chemical vapor deposition （PMOCVD） was first adopted to epitaxy of InAlN-related heterostructures, and excellent crystalline and electrical properties were obtained. Furthermore, the first domestic InAlN-based high-electron mobility transistor （HEMT） was fabricated. Relying on the PMOCVD in combination with special GaN channel growth approach, high-quality InAlN/GaN double-channel HEMTs were successfully achieved for the first time. Additionally, other potentiality regarding to AlGaN channel was demonstrated through the successful realization of nearly lattice-matched InAlN/AlGaN heterostructures suitable for high-voltage switching applications. Finally, some advanced device structures and technologies including excellent work from several research groups around the world are summarized based on recent publications, showing the promising prospect of InAlN alloy to push group III-nitride electronic device performance even further.     

Progress of graphene growth on copper by chemical vapor deposition: Growth behavior and controlled synthesis

Recently,chemical vapor deposition (CVD) on copper has been becoming a main method for preparing large-area and highquality monolayer graphene.In this paper,we first briefly introduce the preliminary understanding of the microstructure and growth behavior of graphene on copper,and then focus on the recent progress on the quality improvement,number of layers control and transfer-free growth of graphene.In the end,we attempt to analyze the possible development of CVD growth of graphene in future,including the controlled growth of large-size single-crystal graphene and bilayer graphene with different stacking orders.     

玻璃陶瓷基板上铜薄膜的化学气相沉积

使用低介电常数基板和高电导率、高抗电迁移的金属Cu进行布线,可以提高高密度电子封装的传输速度和可靠性。采用乙酰丙酮铜作为前驱体,在常压下利用化学气相沉积技术对玻璃陶瓷基板进行Cu薄膜金属化。利用热重分析、X射线衍射和扫描电子显微镜等技术对前驱体、Cu薄膜进行分析观察。结果表明:影响Cu导体的电阻的主要因素是沉积温度。在温度为290～310℃,N2气流量为200～350mL/min和H2气流量为450～600mL/min的条件下,获得了致密的Cu薄膜,Cu导体方块电阻为25mΩ。     

化学气相沉积法制备光谱选择性碲膜

用化学气相沉积法制备碲薄膜,其步骤为：通过电化学方法制得碲化氢,碲化氢在室温下分解后在聚乙烯塑料箔上沉积得到碲薄膜.用傅里叶红外光谱仪、紫外/可见/近红外光谱仪、X射线衍射仪及扫描电镜表征碲薄膜的光学性能和结构.结果表明,化学气相沉积法在Mn-O覆盖的聚乙烯塑料箔上沉积得到的碲薄膜在大气窗口（8～13μm）光谱区域具有很高的透过率,同时能阻挡几乎所有的太阳光谱,表明碲薄膜是适用于辐射制冷装置的太阳光辐射屏蔽材料.     

环氧树脂上激光诱导局部化学沉铜

用激光诱导化学沉积方法在非导体环氧树脂基体上实现微区局部、快速化学沉铜，并用卢瑟福背散射和扫描电镜方法对镀层的形貌、性质进行了观测和分析。激光的输出功率密度及照射时间决定了镀斑的面积和厚度。所得镀层比传统方法所得的化学镀层更致密。同时，由于激光照射引起的短时局部高温，使界面的金属原子向光照区基体内部扩散，得到的铜镀层与基体有较好的结合力。     

单源化学气相沉积法制备In2O3纳米线

以乙酰丙酮合铟[In（acac）3]（acac=acetylacetonate）作为单源前驱体,Au为催化剂,采用化学气相沉积法,于较低温度（550℃）下成功制得了In2O3纳米线．用X射线粉末衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）和能量分散光谱（EDS）对In2O3纳米线进行了表征;制得的In2O3纳米线具有单晶结构,平均直径约为80nm,长度达十几微米,其生长服从气一液一固机理．光致发光研究发现,In2O3纳米线在483nm处有一个强的发射峰,这可归因于氧空位的存在．     

Synthesis of carbon nanotube array using corona discharge plasma-enhanced chemical vapor deposition

Carbon nanotube array plays an important role in the area of nanomaterials due to its potential applications, e.g. as field emitter in flat panel display[1,2] and as template for synthesizing arrays of other important nanomaterials[3]. Anodic aluminum oxide (AAO) template possesses an ordered porous structure that is formed through self-or- ganization during anodization[4,5], and is widely used to synthesize one-dimensional nanomaterial arrays[6]. Carbon nanotubes are usually assembled into t…     

Well-aligned carbon nanotube array membrane synthesized in porous alumina template by chemical vapor deposition

A new simple approach was devetoped for preparing wetl-aligned and monodispersed carbon nanotube (CNT) array membrane within the cylindrical pores of anodic aluminum oxide (AAO) template by chemical vapor deposition (CVD). Acetylene and hydrogen were used in the CVD process with Fe-catalyzer at 700°C under 250 Pa. Scanning etectron microscope (SEM) and transmission etectron microscope (TEM) were employed to characterize the resulting highly-oriented uniform hollow tube array which had a diameter of about 250 nm, a tube density of 5.3x10⁸ cm² and a length of about 60 μm. The length and diameter of the tubes depend on the thickness and pore diameter of the template. The growth properties of the CNT array film can be achieved by controlling the structure of the template, the particle size of Fe-catalyzer, the temperature in the reactor, the flow ratio and the deposition time. The highly-oriented and uniform CNT array membrane fabricated by this simple method is very much useful in a variety of applications.     

MOCVD法制备Fe/Mo功能梯度材料

利用金属有机化学气相沉积(MOCVD)方法,以Mo(CO)6,Fe(CO)5为物源,在Al2O3陶瓷基片上制备了 Fe/Mo功能梯度材料,并用XPS,XRD,SEM和台阶仪等技术对其成分分布、物相组成、表面形貌和厚度进行测试 和表征.结果表明:材料的组成沿厚度方向呈连续梯度变化,符合功能梯度材料的变化规律.     

Synthesis of trans-bis(glycin- ato) copper(II) complex nanorods by room tempera- ture solid-state reaction

One-dimensional (1D) nano materials have attractedconsiderable attention due to their broad applications inoptics, magnetism, and microsystems electronics, etc.[1,2].Different approaches have been used to prepare 1D nano-materials including vapor evaporation method[3], hydro-thermal synthesis method[4], laser ablation method[5], mi-crowave irradiation method[6], carbon nanotube-confinedtemplate method[7] and other methods. Most of these syn-thetic efforts have been focused on carbon nanotubes,…     

Synthesis of trans-bis（glycinato） copper（Ⅱ） complex nanorods by room temperature solid-state reaction

Trans-[Cu(glyo)2(H2O)] nanoparticles with average diameters about 20-30 nm were prepared by onestep room temperature solid-state reaction. Trans-[Cu(glyo)2]nanorods with diameters ranging from 100 to 150 nm and lengths up to several μm were also prepared by one-step room temperature solid-state reaction in the presence of a suitable nonionic surfactant PEG400. The chemical composition and structural features of the products were investigated by elemental analyses, XRD, TG, SEM and TEM, respectively. The mechanisms of formation were also discussed.     

采用热丝化学气相沉积法制备SiCN薄膜的研究

采用热丝化学气相沉积(HFCVD)系统,在单晶Si衬底上制备SiCN薄膜。所采用的源气体为高纯的SiH4,CH4和N2。用原子力显微镜(AFM)、X线衍射谱(XRD)和X线光电子能谱(XPS)对样品进行表征与分析。研究结果表明:SiCN薄膜表面由许多粒径不均匀、聚集紧密的SiCN颗粒组成;薄膜虽然已经晶化,但晶化并不充分,存在着微晶和非晶成分,通过Jade软件拟合计算出薄膜的结晶度为48.72%;SiCN薄膜不是SiC和Si3N4的简单混合,薄膜中Si,C和N这3种元素之间存在多种结合态,主要的化学结合状态为Si—N,Si—N—C,C—N,N=C和N—Si—C键,但是,没有观察到Si—C键,说明所制备的薄膜形成了复杂的网络结构。     

合成参数对MOCVD法生长氧化锌纳米针的影响

使用脉冲液滴注入式MOCVD,在金膜裹覆的MgO(100)衬底上于500℃合成氧化锌纳米针.纳米针为晶态并且在XRD谱线上主要呈现ZnO的4个衍射强峰(100)、(002)、(101)及(004).金没有起到催化剂的作用,在较薄(2.4nm)金膜上生长的纳米针密度较高且直径较小.500℃是ZnO纳米针较佳的合成温度,在温度不低于550℃时合成的是片状ZnO.每周期前驱体的注入剂量对纳米针的形貌有显著影响.充足的注入剂量(6.8mg/周期)能够保证纳米针合成,而较低的注入剂量(3.4mg/周期)将会合成较短且直径较小的纳米针.     

Catalyst enhanced chemical vapor deposition of nano-particle nickel films on teflon surface

Films formed with nanosized nickel particles on teflon surface were prepared by means of catalyst enhanced chemical vapor deposition (CECVD) with Ni(dmg)₂, Ni(acac)₂, Ni(hfac)₂, Ni(TMHD)₂, and Ni(cp)₂ as precursors, and complexes Pd(hfac)₂, PdCl₂ and Pd(η ³-2-methylallyl)acac as catalyst under carrier gas (H₂). The film growth rate depends on the precursors and substrate temperature. The chemical value, purity and surface morphology of the Ni particle films were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The films obtained were shiny with silvery color, and consisted of grains with a particle size of 50–140 nm. The Ni was metallic of which the purity was about 90%–95% from XPS analysis. SEM micrograph showed that the film had good morphology.      

Fabrication of multi-level branched metal nanowires by AAO template electrodeposition

One-dimensional nanomaterials have received con- siderable attention over the past decade because of their novel physical and chemical properties and potential applications in future nanodevices[1-4]. By manipulat- ing their texture, size and morphology, …     

化学镀法制备镍包铜复合粉末

采用化学镀法制备镍包铜复合粉末,通过研究化学镀过程中还原剂、络合剂及稳定剂的质量浓度、温度、pH值等因素对沉积速率的影响规律得出化学镀镍的优化条件.利用XRD、SEM和EDS等测试手段对优化条件下制备的复合粉末进行表征.研究结果表明:当硫酸镍质量浓度30g·L-1,铜粉质量浓度10g·L-1,联氨质量浓度60g·L-1,柠檬酸钠质量浓度50g·L-1,硫脲质量浓度10~20mg·L-1,控制温度80~90℃,pH=10,超声功率50W时,镀层沉积速度较快,复合粉末表面镍包覆层均匀,包覆层厚度为0.29μm.     

Synthesis of carbon nanotube array using corona discharge plasma-enhanced chemical vapor deposition

A corona discharge phasma-enhanced chemical vapor deposition with the features of atmospheric pressure and low temperature has been developed to synthesize the carbon nanotube array ,The array was synthesized from methane and hydrogen mixture in anodic aluminum oxide template channels in that cobalt was electrodeposited at the bottom.The characterization results by the scanning electron microscopy,transmission electron microscopy,energy dispersive X-ray spectroscopy and Raman spectroscopy indicate that the array consists of carbon nanotubes with the diameter of about 40 nm and the length of more than 4 μm, and the carbon anotubes are mainly restrained within the channels of templates.     

放电电流对热阴极等离子体化学气相沉积金刚石膜影响

建立了快速沉积高品质金刚石膜的热阴极辉光放电等离子体化学气相沉积新方法. 相对于常规冷阴极辉光放电而言,热阴极辉光放电是一种新型放电形式,具有许多新的特性,其中重要一点是具有较高的放电电流(6.0～10.0 A). 较高的放电电流既是热阴极辉光放电本身的突出特点,同时对于化学气相沉积金刚石膜工艺也产生重要影响. 实验研究了放电电流于金刚石膜沉积速率、表面形貌和热导率的影响,发现由于放电电流影响辉光放电的等离子体区和阳极区,进而对金刚石膜的沉积速率和品质有很大影响. 特别是通过放电电流的提高,可以有效地提高金刚石膜的品质,这对于制备优质金刚石膜产品有重大意义.     

金属熔积直接成形翘曲变形的有限元分析

为了研究不同热边界条件对熔积直接成形金属零件翘曲变形的影响,运用有限元法建立了三维模型,通过变换冷却和加热条件来分析直壁件熔积成形过程在不同热边界条件成形过程中温度、应力变化和最终翘曲变形.模拟结果表明：熔积过程中运用随焊冷却技术,能使熔积层温度迅速降到接近环境温度,并在随后的时间内保持很低的温度梯度,从而减小了冷却阶段的应力水平,使得翘曲变形量降低;而熔积成形前对基板预热处理会增加热积累和温度梯度,导致残余应力及翘曲变形量的增加.     

Synthesis of nano onion-like fullerenes by using Fe/Al2O3 as catalyst by chemical vapor deposition

Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400℃ by using Fe/Al₂O₃ as catalyst. The product was refluxed in 36% concentrated HCl at 60℃ for 48 h in order to remove the catalyst support. The samples were examined by scanning and high resolution transmission electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results show that nano onion-like fullerenes encapsulating a Fe₃C core were obtained. These had a structure of stacked graphitic fragments, with diameters ranging from 15―50 nm. When the product was further heat- treated at 1100℃ for 2 h, nano onion-like fullerenes with a clear concentric graphitic layer structure were obtained. The growth mechanism of nano onion-like fullerenes encapsulating metal cores is suggested to follow a vapor-solid growth model.