Field electron emission of diamond films on nanocrystalline diamond coating by CVD method

Generally, nucleation and growth of diamond were difficult on substrates without being pretreated when diamond films were prepared with the chemical vapor deposition (CVD) method. To improve nucleation, two methods were adopted; one is mechanically treating sur-faces of substrates with superhard particles, the other is introducing substrate bias to the substrates. However, these two processes were difficult to bring about industri-alization owing to their complicated procedures and the diffic…     

影响CVD金刚石断裂强度的因素

按照Griffith微裂纹理论,讨论了影响CVD金刚石断裂强度的因素。结果表明,较高的生长温度,较低的生长速率,较小的晶粒尺寸,较少的微观缺陷,较高的金刚石纯度,可以提高CVD金刚石的断裂强度。     

Hydrogen distribution in CVD diamond films prepared by DC arcjet operating at gas recycling mode

Hydrogen distribution and content in diamond films deposited by DC arcjet under gas recycling mode was evaluated by nuclear reaction analysis (NRA). The films were characterized using scanning electron microscopy, X-ray diffraction and Raman spectrometry. The NRA results show that the hydrogen content in diamond films was approximately 0.6% (substrate temperature 770℃), and strongly depended on the substrate temperature. It was that the hydrogen content increased with the increase of the substrate temperature. The possibility of hydrogen trapping in the films was also discussed.     

气体循环条件下等离子体喷射CVD金刚石膜的生长稳定性和品质

在气体循环条件下采用H2、CH4和Ar的混合气体,利用100kW直流电弧等离子喷射CVD系统,在850和950℃下在Mo衬底上沉积了不同厚度的金刚石膜;并利用扫描电镜(SEM)、X射线衍射(XRD)和Raman光谱对膜的形貌、品质、取向和残余应力进行了分析.结果表明:在850℃下,随着金刚石膜厚度的增加,膜的品质不断提高,残余应力逐渐减小,且残余应力为拉应力,膜的生长稳定性很好;在反应气体流速不变的条件下,相比950℃沉积的厚度为120μm的金刚石膜,在850℃下沉积的厚度为110μm的金刚石膜有更好的生长稳定性,膜的品质更高,残余应力更小.     

Relationship between texture and residual macro-strain in CVD diamond films based on phenomenological analysis

The relationship between texture and elastic properties of chemical vapor deposition (CVD) diamond films was analyzed based on the phenomenological theory, which reveals the influence of crystalline orientation and texture on the residual macro-strain and macro-stress. The phenomenological calculations indicated that the difference in Young's modulus could be 15% in single diamond crystals and 5% in diamond films with homogeneously distributed strong fiber texture. The experimentally measured residual strains of free-standing CVD diamond films were in good agreement with the correspondingly calculated Young's modulus in connection with the multi-fiber textures in the films, though the difference in Young's modulus induced by texture was only around 1%. It is believed that texture should be one of the important factors influencing the residual stress and strain of CVD diamond films.     

声表面波器件金刚石薄膜基片的制备工艺

为制备高质量的声表面波器件,探索金刚石薄膜的沉积工艺,采用直流电弧等离子体喷射化学气相沉积技术和特殊的复合衬底技术,在单晶硅衬底上制备了大面积、高质量的金刚石薄膜,成功解决了单晶硅衬底在沉积金刚石薄膜过程中产生的变形问题.研究了甲烷浓度和沉积温度对金刚石薄膜质量的影响,优化了沉积工艺.结果表明,甲烷气体体积分数为1.8%时,晶粒最为细小,同时金刚石薄膜的表面粗糙度最小,表面最为光滑.衬底温度为1000℃时生长的金刚石薄膜的晶粒尺寸较小.     

Ohmic contact properties of p-type surface conductive layer on H-terminated diamond films prepared by DC arc jet CVD

With the advantages of high deposition rate and large deposition area, polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD) are considered to be one of the most promising materials for high-frequency and high-power electronic devices. In this paper, high-quality self-standing polycrystalline diamond films with the diameter of 100 mm were prepared by DC arc jet CVD, and then, the p-type surface conductive layer with the sheet carrier density of 1011-1013 cm?2 on the H-terminated diamond film was obtained by micro-wave hydrogen plasma treatment for 40 min. Ti/Au and Au films were deposited on the H-terminated diamond surface as the ohmic contact electrode, respectively, afterwards, they were treated by rapid vacuum annealing at different temperatures. The properties of these two types of ohmic contacts were investigated by measuring the specific contact resistance using the transmission line method (TLM). Due to the formation of Ti-related carbide at high temperature, the specific contact resistance of Ti/Au contact gradually decreases to 9.95 × 10?5 Ω·cm2 as the temperature increases to 820℃. However, when the annealing temperature reaches 850℃, the ohmic contact for Ti/Au is degraded significantly due to the strong diffusion and reaction between Ti and Au. As for the as-deposited Au contact, it shows an ohmic contact. After annealing treatment at 550℃, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.     

酸刻蚀处理对Si(100)和Si(111)上制备CVD金刚石膜的影响

对Si(100)和Si(111)采用相同的酸刻蚀工艺,采用热丝化学气相沉积法(HFCVD)制备金刚石膜.用扫描电子显微镜、X线衍射仪和X线应力测试仪对样品的形貌、织构及残余应力进行检测、分析.研究结果表明:沉积3 h后,Si(100)和Si(111)基体上均生长出晶形比较完整,呈柱状晶方式生长的金刚石薄膜;此外,Si(100)金刚石膜表面分布着大量的微孔,通过调整沉积工艺可控制微孔的数量和尺寸,而Si(111)金刚石膜表面无微孔出现;2种基体所得薄膜都存在(111)织构,后者Si(111)还有一定的(110)织构;2种基体经酸刻蚀之后制得薄膜均无鼓泡剥离现象,二者的残余应力相差不大.     

CVD金刚石薄膜表面的卤素修饰

金刚石是一种集多种优良性能于一体的功能材料,但是,金刚石薄膜sp^3碳构造的高稳定性导致其表面活性不足,无法满足各种功能性表面的需要．本文从化学修饰角度,研究了卤素在金刚石薄膜表面导入的方法和修饰后的应用,并对修饰后的金刚石表面进行了XPS表征．结果表明,卤素已成功的修饰到了金刚石薄膜表面．     

Main production methods and application of CVD diamond film

】　介绍了化学气相沉积金刚石薄膜的主要制备方法热灯丝法、微波法、等离子体喷射法、火焰燃烧法。CVD金刚石膜的应用。     

化学气相沉积（CVD）金刚石薄膜的主要制备方法及应用

介绍了化学气相沉积金刚石薄膜的主要制备方法：热灯丝法、微波法、等离子体喷射法、火焰燃烧法。 Ｃ Ｖ Ｄ 金刚石膜的应用。     

CVD金刚石厚膜钎焊工艺的研究

探讨了加热温度和钎料加入状态对真空钎焊CVD金刚石厚膜与硬质合金接头性能的影响，并对金刚石厚膜与Ag—Cu—Ti钎料的微观连接机理进行分析。结果表明：在940℃用90(Ag72—Cu)—10Ti钎料箔得到的接头强度较高，钎料中Ti与金刚石生成TiC是实现冶金连接的主要因素。     

Optical characterization of single-crystal diamond grown by DC arc plasma jet CVD

Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition (CVD) were examined using a low-temperature photoluminescence (PL) technique. The results show that most of the nitrogen-vacancy (NV) complexes are present as NV-centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N₂ incorporation and the high mobility of vacancies under growth temperatures of 950-1000℃. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy (Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition (MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV- centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.     

等离子喷射CVD金刚石膜制备过程中的断弧保护

通过对等离子体喷射CVD金刚石设备的控制电路的改进,增加了沉积过程中在断弧情况下对已经沉积的膜的保护.该部分是在不影响开机点火的前提下,从主电流(电弧电流)取信号来控制冷却系统,使已生成的金刚石膜缓慢地冷却到室温,减小金刚石膜与衬底因温度瞬间下降而造成的相互作用力,金刚石内应力的释放相对减少.宏观裂纹明显减少,提高膜的完整性和产品的利用率和出材率.     

用浮力法测量金刚石膜的密度

本文报道了一种测量金刚石膜密度的浮力法.这种方法的特点是快速、方便、准确和实用.     

干摩擦条件下金刚石复合膜摩擦学性能

在干摩擦条件下利用 SRV磨损试验机比较了在硬质合金基体上金刚石薄膜、石墨 /金刚石复合膜以及硬质合金 3种试样的摩擦学性能。利用扫描电子显微镜观察了试样和磨痕的表面形貌。利用表面形貌仪测试了磨损体积。研究了振动频率对试样的摩擦学性能影响。结果表明 ,在干摩擦条件下 ,金刚石薄膜与石墨 /金刚石复合膜的摩擦学性能差别不大 ,二者的磨损机理均为微断裂磨损。在干摩擦条件下 ,高频时金刚石薄膜的耐磨性是硬质合金耐磨性的 8～ 10倍 ,其原因是硬质合金的磨损机理存在着从粘着磨损到微断裂磨损的转变     

CVD金刚石膜沉积设备的稳流控制电路

研制了DCPLASMAJETCVD金刚石膜沉积设备电源的稳流控制电路。该电路利用负反馈原理,通过SG3524调节输出脉冲的占空比,推动IGBT,为磁饱和电抗器提供控制电流,达到电源稳定输出电流的目的。     

功率器件金刚石薄膜用热沉的传热模型及模拟

目的 对金刚石薄膜在改善电力电子器件热特性的应用进行初步的探索.方法 将金刚石薄膜用于电力电子器件(横向二极管)的热沉,建立横向二极管的导热模型,采用Microso:ft VisualBasie 6.0程序设计语言对导热模型进行计算机模拟仿真.结果 当金刚石薄膜的厚度达到约50μm以上时,所获得的散热效果较显著,但并不是随着金刚石薄膜厚度的增加,器件的温度随之线性降低,当h>100 pan以后,温度降低变缓.结论 金刚石薄膜作为电力电子器件的导热层能明显地降低器件的温升.     

Orientation variation along growth direction of millimeter free-standing CVD diamond thinned by mechanical grinding

A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were characterized by X-ray diffraction and Raman spectroscopy, respectively. The results show a random grain-orientation distribution during the initial growth stage. As the film thickness increases, the preferred orientation of the diamond film changes from (111) to (220), due to the competitive growth mechanism. Twinning generated during the nucleation stage appears to stabilize the preferential growth along the 〈110〉 direction. The interplanar spacing of the (220) plane is enlarged as the film thickness increases, which is caused by the increase of non-diamond-phase carbon and impurities under the cyclic gas. In addition, the quality of the diamond film is barely degraded during the growth process. Furthermore, the peak shift demonstrates a significant inhomogeneity of stress along the film growth direction, which results from competitive growth.     

金刚石节块的抗弯强度分析

首先通过三点弯曲试验 ,研究了金刚石表面镀钛处理对抗弯强度的影响 ,提出了含金刚石节块的σbb的大致估计公式 ;设计了正交试验 ,研究了诸因素对Cu 10Sn基金刚石节块的抗弯强度的影响 ;用扫描电镜观察分析了试样断面