利用高频Plasma CVD在蓝宝石衬底上生长立方GaN缓冲层及其光学性质

研究了采用高频 Plasma CVD技术在较低温度下 (30 0— 40 0℃ )生长以 Ga N为基的 - 族氮化物的可行性 ,在蓝宝石衬底上生长了 Ga N缓冲层 .热处理后的光致发光谱和 X光衍射表明 ,生长的 Ga N缓冲层为立方相 ,带边峰位于 3.15 e V.在作者实验的范围内 ,最优化的 TMGa流量为 0 .0 8sccm (TMAm=10 sccm时 ) ,XPS分析结果表明此时的 Ga/ N比为 1.0 3.这是第一次在高 / 比下得到立方 Ga N.相同条件下石英玻璃衬底上得到的立方 Ga N薄膜 ,黄光峰很弱 。

A New Approach to Plasma CVD of TiO_2 Photocatalyst on γ-Al_2O_3 Pellet Filled in Dielectric Barrier Discharges at Atmospheric Pressure

A supported TiO2/γ-Al2O3 photocatalyst has been prepared by γ-Al2O3 pellet-filled dielectric barrier discharges induced plasma CVD at atmospheric pressure and room temperature. The TiO2/γ-Al2O3 photocatalyst exhibits higher photocatalytic activity than Degussa P25, and much higher photocatalytic activity than that prepared by thermal CVD.

Tuning Effect of N_2 on Atmospheric-Pressure Cold Plasma CVD of TiO_2 Photocatalytic Films

To deposit TiO2 films through plasma CVD, the partial pressure ratio of O2 to TIC14 should be greater than the stoichiometric ratio （PO2/PTiCl4 〉 1）. However, this may lead to the formation of powder instead of film on the substrate when using volume dielectric barrier discharge （volume-DBD） at atmospheric pressure. In this study, by adding N2 into the working gas Ar, TiO2 photocatalytic films were successfully fabricated in the presence of excess O2 （PO2/PTiC14 = 2.6） by using a wire-to-plate atmospheric-pressure volume-DBD. The tuning effect of N2 on the deposition of TiO2 film was studied in detail. The results showed that by increasing the N2 content, the deposition rate and particle size of the TiO2 film were reduced, and its photocatalytic activity was enhanced. The tuning mechanism of N2 is further discussed.

Low Temperature Plasma CVD Grown Graphene by Microwave Surface-Wave Plasma CVD Using Camphor Precursor

Hydrocarbon precursor such as methane has been widely used to grow graphene films and the methods of growing quality graphene films are dominated by thermal CVD （chemical vapor deposition） system. Graphene films grown by plasma process are generally highly defective which in turns degrade the quality of the films. Here, using a green precursor, camphor we demonstrate a simple and economical method to get high-quality graphene film on copper substrate by micro wave surface-wave plasma CVD at relatively low temperature 550℃. Graphene film grown using camphor shows superior quality than that of the film grown using methane. Results revealed that camphor precursor is a good alternative to hydrocarbon precursors for graphene research.

PREPARATION OF IODINE-INCLUDED CARBON USING RF PLASMA CVD

For the aim of synthesis of the carbon-iodine compound, the preparation of iodin e-included carbon using RF plasma CVD was studied. Iodine-included carbon was sy nthesized on Si substrate using ICP type RF plasma CVD apparatus. C2H5OH and I2 dissolved C2H5OH was used as reactant gases. As a result, surface morphologies o f Iodine included carbon films showed flat surfaces for each samples. On the str ucture of films estimated by Raman spectroscopy, amorphous carbon was recognized . And I2 peaks were observed in XPS spectra. As a result of friction test, frict ion coefficient of the sample growth with C2H5OH showed about 0.45. On the other hand, that of the sample with I2-C2H5OH showed about 0.3 and decrease of fricti on coefficient was recognized. Iodine inclusion for carbon materials can be achi eved by RF plasma CVD using an I2-C2H5OH reactant. The coefficient of iodine-inc luded carbon showed lower than of without iodine

Columnar growth of crystalline silicon films on aluminium-coated glass by inductively coupled plasma CVD at room temperature

Silicon films were grown on aluminium-coated glass by inductively coupled plasma CVD at room temperature using a mixture of SiH4 and H2 as the source gas. The microstructure of the films was evaluated using Raman spectroscopy, scanning electron microscopy and atomic force microscopy. It was found that the films are composed of columnar grains and their surfaces show a random and uniform distribution of silicon nanocones. Such a microstructure is highly advantageous to the application of the films in solar cells and electron emission devices. Field electron emission measurement of the films demonstrated that the threshold field strength is as low as -9.8V/μm and the electron emission characteristic is reproducible. In addition, a mechanism is suggested for the columnar growth of crystalline silicon films on aluminium-coated glass at room temperature.

ECR Plasma CVD淀积介质膜的工艺模拟

以实验数据为基础，运用人工神经网络方法，建立了电子回旋共振等离子体化学气相沉积（ＥＣＲ Ｐｌａｓｍ ａ ＣＶＤ）淀积硅的氮、氧化物介质膜折射率ｎ 与气流配比Ｑ（Ｎ２）／Ｑ（ＳｉＨ４）和Ｑ（Ｏ２）／Ｑ（ＳｉＨ４）关系的数学模型，此模型在给定气流配比Ｑ（Ｎ２ ）／Ｑ（ＳｉＨ４）和Ｑ（Ｏ２）／Ｑ（ＳｉＨ４）时所预测的成膜折射率跟实验值符合得很好，该数学模型为ＥＣＲ Ｐｌａｓｍ ａ ＣＶＤ淀积全介质光学膜的工艺模拟打下坚实的基础。

Pulsed Supermagnetron Plasma CVD of a-CN_x:H Electron-Transport Films for Au/a-CN_x:H/p-Si Photovoltaic Cells

Hydrogenated amorphous carbon nitride (a-CNx:H) films were formed on p-Si wafers set on a lower elec-trode by pulsed supermagnetron plasma CVD using i-C4H10 and N2 gases. Lower electrode RF power (LORF) of 13.56 MHz (50 - 800 W) was modulated by a 2.5-kHz pulse at a duty ratio of 12.5%, and upper electrode RF power (UPRF) of 50 - 400 W was supplied continuously. The optical band gap decreased with an increase in LORF at each UPRF. The open circuit voltage of Au/a-CNx:H/p-Si photovoltaic cells (a-CNx:H film thickness: 25 nm) was about 200 mV for each cell, and the short circuit current density and energy conversion efficiency increased with LORF for each UPRF. The highest energy conversion efficiency of 0.81% was obtained at UPRF/LORF of 200/800 W.

ECR plasma CVD法淀积980 nm大功率半导体激光器端面光学膜技术

介绍了电子回旋共振等离子体化学气相沉积（简称ECRplasmmaCVD）法淀积980nm大功率半导体激光器两端面光学膜的工艺条件，探索了膜系监控的方法和优越性，讨论了这种淀积方法的优点和淀积的光学膜的优良特性。

采用DC Arc Plasma JetCVD方法沉积微/纳米复合自支撑金刚石膜

在30kW级直流电弧等离子体喷射化学气相沉积(DC Arc P lasm a Jet CVD)设备上,采用Ar-H2-CH4混合气体,通过调节甲烷浓度以及控制其他沉积参数,在Mo衬底上沉积出微/纳米复合自支撑金刚石膜。实验表明,当微米金刚石膜层沉积结束后,在随后的沉积中,随着甲烷浓度的增加,金刚石膜表面的晶粒大小是逐渐减小的。当甲烷浓度达到20%以上时,金刚石膜生长面晶粒呈现菜花状的小晶团,膜体侧面已经没有了粗大的柱状晶,而是呈现出光滑的断口,对该层进行拉曼谱分析显示,位于1145 cm-1附近有一定强度的散射峰出现。这说明所沉积的晶粒全部变为纳米级尺寸。

ECR Plasma CVD淀积光电器件介质膜的工艺模拟

以实验数据为基础,运用人工神经网络方法,建立了电子回旋共振等离子体化学气相沉积(ECRPlasmaCVD)淀积硅的氮、氧化物介质膜的折射率、速率与气流配比Q(N2)/Q(SiH4)和Q(O2)/Q(SiH4)关系的数学模型,此模型在给定气流配比Q(N2)/Q(SiH4)和Q(O2)/Q(SiH4)时所预测的成模折射率跟实验值符合得很好,为ECRPlasmaCVD淀积全介质光学膜的工艺打下坚实的基础。

THERMODYNAMIC ANALYSIS AND EXPERIMENTAL VERIFICATION FOR SYNTHESIZING SILICON NITRIDE NANOPARTICLES USING RF PLASMA CVD

Silicon nitride nanoparticles were synthesized by radio-frequency (RF) plasma chemical vapor deposi-tion (PCVD) using silicon tetrachloride and ammonia as precursors, and argon as carrier gas. By assuming chemical thermodynamic equilibrium in the system, a computer program based on chemical thermodynamics was used to cal-culate the compositions of the system at different initial concentrations and final temperatures. At first, five elements and thirty-four species were considered. The effects of temperatures, and concentrations of ammonia, hydrogen and nitrogen on the equilibrium compositions were analyzed. It was found that the optimal reaction temperature range should be 1200 to 1500 K to obtain the highest conversion and yield of Si3N4. The inlet position of ammonia should be lower than that of silicon tetrachloride, and both should be located at the tail of the plasma torch. The best mole ratio of ammonia to silicon tetrachloride was found to be about 6. Later, the influences of water (and oxygen) were considered, and 17 additional species were included in the computations. It was found that oxygen or water content in the raw materials should be as low as possible in order to have high nitride content in the produced Si3N4. Nitrogen or hydrogen might be used to replace some or even all the argon to improve the yield of silicon nitride and reduce the cost. The ratio of ammonia to silicon tetrachloride should be high enough to obtain high conversion, but not exces-sively high to reduce the oxygen content due to the existence of water in ammonia. The simulated results were veri-fied by experiments.

OES study of the gas phase during diamond films deposition in high power DC arc plasma jet CVD system

This paper used optical emission spectroscopy （OES） to study the gas phase in high power DC arc plasma jet chemical vapour deposition （CVD） during diamond films growth processes. The results show that all the deposition parameters （methane concentration, substrate temperature, gas flow rate and ratio of H2/Ar） could strongly influence the gas phase. C2 is found to be the most sensitive radical to deposition parameters among the radicals in gas phase. Spatially resolved OES implies that a relative high concentration of atomic H exists near the substrate surface, which is beneficial for diamond film growth. The relatively high concentrations of C2 and CH are correlated with high deposition rate of diamond. In our high deposition rate system, C2 is presumed to be the main growth radical, and CH is also believed to contribute the diamond deposition.

Influence of plasma condition on carbon nanotube growth by rf-PECVD

Carbon nanotubes(CNTs)have been synthesized from Ar-CH_4 mixtures using rf-plasma enhanced chemical vapor deposition(rf-PECVD)at 500oC.Reduction gases such as H_2 and NH_3 were found unnecessary for carbon nanotube formation compared to thermal CVD.The relationship between the growth of CNTs and the plasma condition in PECVD has been investigated by in situ self bias measurement.Plasma conditions were controlled by changing the interelectrode distance,rf power and the applied substrate negative bias.By increasing the interelectrode distance and rf power,the spatial density of CNTs was on a rise as a result of the increase in ions density and self bias.As the applied substrate negative bias increased,the spatial density of CNTs decreased possibly due to the positive ions over bombarding effect.

Preparation and Characterization of High Quality Diamond Films by DC ArcPlasma Jet CVD Method

Under optimal conditions free-standing high quality diamond films were prepared by DC arc plasma jet CVD method at a growth rate of 7-10 Pm/h. Surface and cross section morphologies of the diamond films were observed by SEM. Raman spectrometer wasused to characterize the quality of diamond films. The IR transmittivity measured by IR spectrometer is close to the theoretical value ofabout 71% in the far infrared band. The thermal conductivity measured by photothermal deflection exceeds 18 W/cm' K. <l 10> is thepreferential growth orientation of the films detected by X-ray diffractometer. As s result, the extremely high temperature of DC arc plasma jet can produce supersaturated atomic hydrogen, which played an important role in the process for the deposition of high quality diamond films.

线形同轴耦合式微波等离子体CVD法制备金刚石薄膜

线形同轴耦合式微波等离子体CVD装置是一种利用微波天线产生轴向分布的等离子体柱的新型微波等离子体CVD装置。由于它产生的等离子体是沿微波天线分布的 ,因而可避免石英管式、石英钟罩式以及不锈钢谐振腔式微波等离子体CVD装置中等离子体的分布容易受到金属工件位置干扰的缺点。本文将首先讨论线形同轴耦合式微波等离子体CVD装置的工作原理 ,其后介绍利用此装置进行的金刚石薄膜沉积实验的初步结果。实验结果表明 ,利用线形同轴耦合式微波等离子体CVD装置 。

ECR等离子体刻蚀增强机械抛光CVD金刚石

采用电子回旋共振(ECR)等离子体刻蚀与机械抛光相结合的方法抛光化学气相沉积(CVD)金刚石,运用扫描电镜、Raman光谱观察、分析了刻蚀与抛光后金刚石的表面形貌和质量变化,并与单纯的机械抛光相比较,研究了等离子体刻蚀对后续机械抛光的影响,结果发现:金刚石经ECR等离子体刻蚀后非晶碳含量有一定程度降低,刻蚀过程在金刚石晶面形成的疏松表面有利于机械抛光,金刚石表面平均粗糙度更加快速降低。对比实验表明等离子体刻蚀对机械抛光前期的抛光效率的增强效果更为明显,在ECR等离子体刻蚀后的金刚石样品经10min机械抛光后粗糙度从7.284下降到1.054μm,而直接机械抛光30min时金刚石的表面粗糙度为1.133μm,在机械抛光的初始阶段,等离子体刻蚀后的机械抛光效率是单纯机械抛光效率的3倍。最终,经过三次重复刻蚀后机械抛光,金刚石表面粗糙度降为0.045μm。

辅助加热PCVD-TiN薄膜的性能及结构分析

研究了反应气体对辅助加热ＰＣＶＤ－ＴｉＮ薄膜制备的影响。结果表明，提高反应气体中ＴｉＣｌ４的含量ＴｉＮ薄膜内的氯含量基本不变。提高反应气体中的Ｈ２／Ｎ２比可以略降低薄膜内的氯含量，在Ｈ２／Ｎ２＝２、ＴｉＣｌ４约为１０％时ＴｉＮ薄膜的硬度最高，ＴｉＮ薄膜仍呈柱状结构，具有较强的（２００）晶面织构。

用于合成金刚石薄膜的微波等离子体CVD系统

研制了一套功率容量大、结构合理、工作稳定的微波等离子体ＣＶＤ系统。描述了系统的基本结构和性能，讨论了它的特点。作者利用该系统，在单晶Ｓｉ等衬底材料上成功地合成了金刚石薄膜。

CVD金刚石涂层拉拔模的制备

针对拉制铝管用尼龙模具寿命短和硬质合金模具粘铝的问题,采用微波等离子体CVD法在硬质合金拉拔模内孔壁涂覆金刚石薄膜。通过设计一个特殊支撑结构,引导等离子体进入拉拔模内孔,可实现在内孔8mm深度范围一次沉积出金刚石膜。现场拉拔试验表明,金刚石涂层模拉制的铝管光洁度介于尼龙模和硬质合金模之间,可满足使用要求。