Dependence of surface morphology of CVD diamond films on deposition conditions

ＤｅｐｅｎｄｅｎｃｅｏｆｓｕｒｆａｃｅｍｏｒｐｈｏｌｏｇｙｏｆＣＶＤｄｉａｍｏｎｄｆｉｌｍｓｏｎｄｅｐｏｓｉｔｉｏｎｃｏｎｄｉｔｉｏｎｓＹＡＮＧＧｕｏｗｅｉ（Ｄｅｐｔ．ｏｆＰｈｙｓ．，ＸｉａｎｇｔａｎＵｕｉｖｅｒｓｉｔｙ，Ｘｉａｎｇｔａｎ４１１１０５...     

CVD金刚石膜制备方法及其应用

介绍了金刚石膜的应用和低压下化学汽相沉积金刚石膜的主要方法及其最新进展,并对各种方法的优缺点作了简要评述。     

用催化CVD法研制优质a—Si薄膜

用新的催化ＣＶＤ法在约３５０℃的低温条件下研制出了ａ－Ｓｉ薄膜。本文是利用催化剂，使ＳｉＨ和Ｈ２混合气体在一定温度下反应而裂解，在衬底上沉积ａ－Ｓｉ薄膜。所制出的ａ－Ｓｉ膜膜具有良好的光电特性，光电灵敏度超过１０＾６，电子自旋密度约２．５×１０＾６ｃｍ＾－３。     

用作超大规模集成电路低k材料的有机薄膜

详细介绍了几种可用于超大规模集成电路的低介电常数有机薄膜材料 ,比如聚酰亚胺类有机薄膜、聚对二甲苯类有机薄膜和聚烯链类有机薄膜。比较了这几种薄膜之间的特性和制备工艺 ,并就薄膜的结构和制备方法对性能的影响做了进一步的探讨。     

CdS微晶掺杂TiO2—SiO2复合薄膜的非线性光学特性

采用溶胶－凝胶方法在普通的载玻片上制备了ＣｄＳ微晶掺杂的ＴｉＯ２－ＳｉＯ２复合薄膜。用正硅酸乙酯、钛酸丁酯、醋酸镉作原料，比较了硫脲和硫化乙氨的硫化作用。不同热处理温度、时间的吸收光谱表明，薄膜中存在着量子尺寸效应。采用Ｚ－Ｓｃａｎ技术测量了薄膜的非线性吸收及非线性折射率。     

喷射CVD法制备金刚石厚膜及其内应力分析

采用直流电弧等离子体喷射CVD法制备出金刚石薄膜,利用扫描电子显微镜(SEM)、Raman光谱及X射线衍射(XRD)等研究基底温度对金刚石厚膜生长特性及内应力的影响。结果表明:950℃基底温度生长的金刚石厚膜结晶性能较好,纯度较高;而850℃和1050℃生长的金刚石厚膜表面呈现大量的孪晶缺陷,结晶度较低,同时出现较多的非金刚石碳,纯度较低。随着基底温度的增加,(111)晶面和(311)晶面的衍射峰强度逐渐增强,(220)晶面的衍射峰强度逐渐降低。850℃和950℃基底温度生长的金刚石厚膜的宏观应力和微观应力都呈现出拉应力,1050℃基底温度生长的金刚石厚膜的宏观应力和微观应力都呈现出压应力。     

Molecular view of diamond CVD growth

In this paper, we discuss the simulation of the chemical vapor deposition (CVD) of diamond films on the molecular scale. These simulations are performed using a kinetic Monte Carlo method that combines the surface chemistry that is important to diamond growth with an atomic-scale picture of the diamond surface and its evolving atomic structure and morphology. We address the determination of surface reaction kinetics and growth conditions from experiments and reactor-scale models, and the prediction of polycrystalline film texture and morphology from the molecular-scale results. The growth rates and the concentrations of incorporated point defects as a function of substrate temperature for {100}- and {111}-oriented diamond films are obtained from the molecular-scale growth simulations. The {100} growth rates increase with temperature up to 1200K and then decrease above this value. The {111} growth rates increase with temperature at all of the temperatures studied. The concentrations of point defects in the {100} and {111} films are low at substrate temperatures below 1200K, but increase substantially at higher temperatures. The growth efficiency, measured as the ratio of film growth rate to defect concentration, is maximum between 1100–1200K for both film orientations, suggesting that this temperature range is ideal for CVD diamond growth under the simulated growth conditions.     

Magnetoresistance of evaporated InAs thin films

Thin films of InAs were deposited on mica substrates by means of controlling both source and substrate temperatures. The temperature and geometry dependence of the magnetoresistance for these films were investigated. A continuous range of behavior was observed from films of high electron mobility-low magnetoresistance at one extreme to those of low mobility-high magnetoresistance at the other. The latter type is shown to be due to excess indium which is occluded during evaporation as a result of the lower vapor pressure of arsenic.     

Characterization and optical properties of bismuth chalcogenide films prepared by pulsed laser deposition technique

Thin films of Bi-based chalcogenides were prepared by pulsed laser deposition (PLD) technique according to the stoichiometric formula: Bi₂(Se_1−xTe_x)₃. Their optical properties were studied aiming to find the suitable area of application and the optimum composition amongst the samples under study. X-ray diffraction analysis proved the crystallinity of the deposited samples; in addition, surface roughness and films homogeneity were studied by atomic force microscopy (AFM) confirming the suitability of PLD technique to prepare homogenous and smooth films of the concerned alloys. Absorption coefficient calculations showed higher absorption values of 5×10⁵ and 6×10⁵ cm⁻¹ for Te contents of 90% and 100% in the Bi₂(Se_1−xTe_x)₃ system respectively. Optical band gap of the concerned films were calculated and found to be in the range of 0.76–1.11 eV, exhibiting comparable values with the previously reported by other authors. Optical studies conformed direct and allowed transitions in all films. Refractive index (n) and dielectric constants (Ɛ_r) and (Ɛ_i) were calculated and studied as a function of the wavelength. Values and behavior of (n), (Ɛ_r) and (Ɛ_i) indicated strong dependence on the composition and the wavelength range.     

Study on optical compund films

Using the compound materials and double e-gun evaporation ,the compound optical films have been successfully deposited on K9 glass substrate.The refractive index of optical compound films deposited in diffeent parameters have been measured and theoretical formula for calculation refractive index of compound films have been derived.Tt is shown that the experimental curve for the variation of re-fractive index with wavelength in 0.4-1.4цm region and the theoretical one agree very well.Using these films,the laser reflecting mirror has been successfully coat-ed.     

Study on optical compound films

ＳｔｕｄｙｏｎｏｐｔｉｃａｌｃｏｍｐｏｕｎｄｆｉｌｍｓＺＨＡＮＧＨＷ（Ｌａｂ．３０３，Ｄｅｐｔ．ｏｆＭａｔｅｒ．ａｎｄＩｎｆｏｒｍ．Ｅｎｇ．，ＵｎｉｖｅｒｓｉｔｙｏｆＥｌｅｃ．Ｓｃｉ．＆Ｔｅｃｈｎｏｌ．ｏｆＣｈｉｎａ，Ｃｈｅｎｇｄｕ６１００５３，ＣＨ...     

半导体金刚石膜的磁阻效应

研究了在硅上Ｐ型异质外延金刚石膜的磁阻效应。实验结果表明金刚石膜有显著的磁阻反应，并与磁阻器件的结构有关。在室温下圆盘形结构的磁阻相对变化在５Ｔ磁场下约为０．８５，而长条形结构只有０．４０。     

Selective deposition of diamond films

Polycrystalline diamond films have been selectively deposited on a silicon surface. A novel process was developed which exposes a patterned, scratch damaged silicon area, surrounded by SiO₂, to a high pressure microwave plasma of hydrogen containing methane. The hydrogen plasma dissociates the methane injected into the reaction chamber, resulting in diamond deposition, which occurs only on the exposed silicon. Under the process conditions described in this work, some in situ plasma etching of the oxide is observed, resulting in little or no growth of diamond in unwanted areas, and further enhancing the selectivity. A variety of patterns and structures have been fabricated. Raman spectroscopy confirmed the films were diamond.     

Photo-assisted metal-organic chemical vapor deposition of CaCu3Ti4O12 (CCTO) thin films

Calcium copper titanate (CaCu₃Ti₄O₁₂) or CCTO is one of the most researched giant dielectric constant materials in recent years. In the present work, incoherent light source based photo-assisted metal-organic chemical vapor deposition (MOCVD) has been used to prepare CCTO thin films on Si/SiO₂ substrates. Key to this unique processing technique is the use of UV radiation as an additional source of energy in conjunction to the thermal energy. The given Photo-assisted MOCVD processing resulted in polycrystalline CCTO growth on a SiO₂ surface. Powder X-ray diffraction and scanning electron microscopy were performed to analyze structural and compositional properties of the CCTO thin film. Ellipsometric measurements indicated a refractive index of 3.03 for the CCTO thin film.     

金刚石薄膜的结构特征与电导率的相关性

讨论了ＣＶＤ金刚石薄膜作为半导体材料的一些基本特性，主要叙述了金刚石薄膜的生长习性和结构特征对其电性能的影响，即其电导率的“尺度交 ”和“晶面效应”，以及这些效应对由金刚薄膜制备的半导体器件性能的影响。     

Room temperature deposition of silicon nitride films using very low frequency (50Hz) plasma CVD

Silicon nitride films have been deposited by low frequency 50Hz plasma CVD using a nitrogen and silane mixture at room temperature. To deposit high quality silicon nitride, the silane fraction in the nitrogen and silane mixture has to be less than 5 %. The refractive index, breakdown field strength and resistivity of the obtained silicon nitride film were 2.0, 1.2x10⁷ V/cm and 6x10¹⁵ Ωcm, respectively. Mechanism of the deposition of high quality silicon nitride is discussed on the basis of the experimentally observed light emission spectrum from the plasma and of the electron energy distribution function in the plasma theoretically calculated by the Boltzmann equation method.     

CVD金刚石热沉封装高功率半导体激光器的热特性

本文以自支撑CVD金刚石膜作为半导体激光器线阵的封装热沉,从而改进其热特性。首先,以电子辅助化学气相沉积(EACVD)制备自支撑金刚石膜。在沉积工艺中,提出了优化O_2流量刻蚀非金刚石相,使金刚石膜品质得到改进,从而提高其导热率。然后,测试了基于不同氧流量下制备金刚石热沉封装的半导体激光器线阵的电光特性,并对封装器件的热特性进行了分析。结果表明:通入O_2流量为每分钟5 sccm时,制备的金刚石热沉导热率可达1 812.3 WK^-1m^-1。O_2流量5 sccm制备金刚石热沉的封装器件的斜率效率为1.30 W/A,电光转换效率最大值可达60.6%。在连续波30 A时,该封装器件的光谱红移波长为2.02 nm,器件工作温度降低4.9 K。器件的传热路径热阻降低28.4%,表现出优异的可靠性。     

Some properties of inn films prepared by reactive evaporation

Some optical and electrical properties of degenerate InN films prepared by a reactive evaporation technique are presented. Thermal stability of these easily dissociated samples is discussed and evidence is presented indicating that the partial pressure of atomic nitrogen rather than diatomic nitrogen is a more fundamental parameter for describing thermal equilibrium. This has important implications for the growth of all group III-nitrides.     

激光抛光化学气相沉积金刚石膜

讨论了激光抛光金刚石膜机理、影响因素,分析了激光抛光金刚石膜理论模型、激光抛光后金刚石膜的粗糙度极限,提出要实现金刚石膜特别是厚膜的精密抛光须考虑激光辅助复合抛光或其它抛光工艺。