金刚石芯LED中衬底及外延材料的研究进展

金刚石作为自然界中热导性最好的材料,在半导体行业的应用越来越广泛。随着LED行业的不断发展,金刚石芯LED也崭露头角。综述了自20世纪50年代以来,金刚石材料作为衬底和外延材料在半导体光电子领域的研究进展。主要从两个方面展开论述:金刚石作为衬底外延GaN的研究进展;以及金刚石本身作为外延材料制备成p-n结、p-i-n结、异质结等半导体器件的研究进展。这些研究充分体现了金刚石材料应用在LED产品中的可行性和优越性,以及应用在大功率LED芯片中的巨大潜力。     

金刚石N型导电研究

金刚石n型材料是近年来金刚石半导体器件研究的关键因而成为半导体材料领域研究的热点之一.本文通过理论计算对n-型材料研究中存在的磷(P)掺杂材料电子激活能量太高及掺硼p-型金刚石材料出现的导电类型转换现象进行了分析和探讨.     

酚醛环氧树脂

耐焊裂的无铅环氧树脂组成物及用其密封的半导体器件；具有优异的透明性、粘结性、和耐热性的半导体器件用粘结剂组成物，半导体器件粘结片，半导体联接电路板，以及半导体设备；半导体器件用的胶粘剂粘结的绝缘带，覆铜层压板，半导体连接用的线路板，和半导体器件；具有优异的流动性和抗热冲击性能的环氧树脂组成物和半导体器件；阻燃环氧树脂组成物及用其密封的半导体器件.     

科学技术部《中国高新技术产业发展报告》(新材料产业部分)(五)

二、金刚石薄膜 CVD(chemical vapour deposition)金刚石具有极其优异的力学、热学、声学、光学、电学、半导体以及化学惰性等性能,作为新金刚石材料80年代问世以来,受到发达国家的高度重视,CVD金刚石技术研究得到较快发展。但是金刚石薄膜在许多领域中的应用产业化技术具有很高的难度,至今尚未真正达到产业化。我国自1987年以来,国家高技术发展计划(863)将CVD金刚石应用技术     

P型和N型金刚石薄膜研究进展

金刚石薄膜有着高的热导率,高的介质击穿场强,高的载流子迁移率以及宽的禁带等优点,是非常理想的功能材料。掺杂使金刚石薄膜具有独特的电学和热学性能,使其在半导体领域具有广阔的应用前景,近年来成为国内外研究的热点之一。综述了金刚石薄膜P型掺杂和N型掺杂的研究现状,对金刚石薄膜N型掺杂研究中存在的问题进行了分析和探索,并对N型金刚石的前景进行了展望。     

ZnO宽带隙半导体及其基本特性

ZnO半导体是宽带隙半导体领域中继GaN和SiC之后的研究热点.同时,作为一种氧化物半导体,ZnO半导体在能带结构、晶格缺陷、抗辐照特性以及电学性质等方面具有特殊性,已有的研究中还存在一些不同的认识.本工作在阐述ZnO的晶体结构和基本性质基础之上,对其能带结构和缺陷特征、电子输运以及P型掺杂等主要的半导体特性研究现状进行了较为全面综述和分析.由于ZnO半导体具有高的激子束缚能、优良的电子输运性质、强抗辐照特性以及低成本和环境友好等显著特征,它是未来半导体光电子领域极具应用潜力的新一代宽带隙半导体材料,但是到目前为止,p型掺杂技术仍然是ZnO半导体器件面临的最大挑战.     

高频大功率金刚石薄膜场效应管的研究进展

随着CVD人工合成金刚石薄膜质量的不断提高,其优异的电学性能在高频、大功率领域特别是场效应管中的应用受到了极大地关注.制作金刚石薄膜场效应管,电子级质量的薄膜、形成良好的接触以及半导体的形成是其关键技术.以此为基础,为达到其在高频大功率下使用的目的,减小栅长和各种寄生参数以及提高耐压和散热能力成为决定其性能优劣的关键因素.本文针对金刚石薄膜场效应管制作的关键技术的突破、H端基表面导电机制、目前高频大功率场效应管的水平以及出现的一些相关在研热点进行了综述,展望了其巨大的优越性和广阔的应用前景.     

扫描近场光学显微技术在半导体材料表征领域应用的研究进展

半导体材料及其光电器件如激光器、探测器以及高速微波器件有着广阔的应用前景。半导体材料的结构和缺陷特性对器件性能起着至关重要的影响,然而对材料进行纳米尺度下的检测、表征无论是理论上还是技术和设备上都需要深入研究和发展,因此扫描近场光学显微技术在半导体材料表征领域有着无可替代的地位。扫描近场光学显微技术突破了传统光学显微技术的衍射分辨率极限的限制,具有超高空间分辨率、超高探测灵敏度等特点,并且是一种非接触性探测,具有无损伤性。简要介绍了扫描近场光学显微镜的原理及在半导体材料研究中的应用,包括量子阱结构中的位错及缺陷的表征,半导体器件的表面复合速率及扩散长度的纳米表征,以及半导体薄膜中的缺陷分布的检测。探讨了目前相关研究领域存在的主要问题,并对其发展趋势和前景进行了展望。     

GaN基材料生长及其在光电器件领域的应用

GaN具有禁带宽度大、热导率高、电子饱和漂移速度大和介电常数小等特点，在高亮度发光二极管、短波长激光二极管、高性能紫外探测器的高温、高频、大功率半导体器件等领域有着广泛的应用前景。介绍了GaN基半导体材料的制备方法，异质结构以及在光电子和微电子器件领域的应用，并讨论了今后的发展趋势。     

Ⅱb型金刚石单晶的制备和半导体特性研究进展

Ⅱb型金刚石由于具有极佳的半导体性能，适合于制造高性能电力电子器件，可以在更高的温度和恶劣的环境下正常工作，是一种有发展前途的高温、大功率半导体材料。本文从结构、合成方法、半导体特性和应用等方面阐述了Ⅱb型半导体金刚石的研究现状，在此基础上提出了今后的研究方向。     

CVD金刚石薄膜半导体材料的研究进展

含Ⅲ族与Ⅴ族元素掺杂的金刚石是宽禁带的半导体材料,同时具有优异的物理和化学特性,在电子器件与光电子器件方面的应用具有极大潜力,成为近几年来国内外研究的热点之一。介绍了目前常用的掺杂方法、技术水平及金刚石半导体的应用前景。     

含硼金刚石单晶制备的研究进展

向人造金刚石中掺杂硼元素可以使金刚石获得比普通金刚石更为优异的物理和机械性能,同时还可以使金刚石具有半导体特性.国内外在含硼金刚石薄膜领域的研究较为深入,相对而言,在含硼金刚石单晶方面的研究较少,尤其是关于制备方法的研究.摸索总结出一种工艺简单、成本低廉、产品质量稳定的含硼金刚石制备方法对于丰富人造金刚石的品种,提高其品质,拓展其应用乃至从总体上提升我国人造金刚石行业的技术水平都有十分重要的意义.本文主要总结了目前国内外生产含硼金刚石单晶的七种方法,分析了他们各自的优缺点,同时简要介绍了作者所在课题组在含硼金刚石制备方法的研究方面所作的一些工作.本文指出了含硼金刚石单晶制备工艺进一步研究的方向和重点,同时对含硼金刚石单晶的应用前景作了展望.     

Shallow donors with high n-type electrical conductivity in homoepitaxial deuterated boron-doped diamond layers

Diamond is a unique semiconductor for the fabrication of electronic and opto-electronic devices because of its exceptional physical and chemical properties. However, a serious obstacle to the realization of diamond-based devices is the lack of n-type diamond with satisfactory electrical properties. Here we show that high-conductivity n-type diamond can be achieved by deuteration of particularly selected homo-epitaxially grown (100) boron-doped diamond layers. Deuterium diffusion through the entire boron-doped layer leads to the passivation of the boron acceptors and to the conversion from highly p-type to n-type conductivity due to the formation of shallow donors with ionization energy of 0.23 eV. Electrical conductivities as high as 2omega(-1) x cm(-1) with electron mobilities of the order of a few hundred cm2 x V(-1) x s(-1) are measured at 300 K for samples with electron concentrations of several 10(16) x cm(-3). The formation and break-up of deuterium-related complexes, due to some excess deuterium in the deuterated layer, seem to be responsible for the reversible p- to n-type conversion. To the best of our knowledge, this is the first time such an effect has been observed in an elemental semiconductor.     

Shallow donors in diamond: Be and Mg

The electronic properties of the impurities Be, Mg and the hydrogen complexes Be–H, Mg–H in diamond have been investigated by first-principle calculations. It is found that the interstitial Be- or Mg- doped diamond are of n-type metal conductivity character. Even at low impurity concentration the doped diamond also appears n-type behavior. The further results indicate that the interstitial Be or Mg doping diamond should be synthesized at H-poor conditions to obtain the n-type material because most of hydrogen atom may result in interstitial Be- and Mg- doped diamond p-type semiconductor or insulator. The substitutional Be and Mg show acceptor behaviors and may compensate other interstitial donors in -diamond. Our results are very helpful to the research of n-type doping in diamond for the future experimental work.     

Bucky-wires and the instability of diamond (111) surfaces in one-dimension

Recent advances in the fabrication and characterization of semiconductor and metallic nanowires are meeting the high expectations of nanotechnolgists. Although diamond has remarkable electronic and chemical properties, development of diamond nanowires has been slow, while the development of carbon nanotube-based technologies continues at a furious pace. Recently, the theoretical and experimental observation of the transformation of nanodiamonds into carbon-onions (and vice versa) has led to a new intermediate phase of carbon, denoted "bucky diamond", with a diamond core encased in an carbon onion-like shell. These findings lead to the question of whether a similar transformation occurs in diamond nanowires. We used ab initio techniques to determine the relaxed structure of diamond nanowires with octahedral surface facets, with results exhibiting delamination of octahedral surfaces, and indicating the formation of "bucky-wires". The effects of surface hydrogenation upon this transition also is examined.     

新一代高导热金属基复合材料界面热导研究进展

热物理性质不同的材料之间存在界面热阻,界面热阻对热传输过程产生极大的影响,并在很大程度上决定了复合材料的导热性能。金刚石颗粒增强金属基复合材料(Metal matrix composites,MMCs)充分发挥了金刚石的高热导率和低热膨胀系数的优点,有望获得高的热导率以及与半导体相匹配的热膨胀系数,可满足现代电子设备在散热能力上提出的越来越高的要求,作为新一代电子封装材料已引起广泛关注。界面热导(界面热阻的倒数)既是决定复合材料导热能力的关键因素,也是研究的难点,复合材料制备工艺、界面改性方式(金属基体合金化或金刚石表面金属化)以及改性金属种类均会影响界面热导。详细论述了界面热导理论及实验研究的最新成果,并对金刚石/金属复合材料在未来研究中面临的主要问题进行探讨。     

正偏压对纳米金刚石薄膜结构和电阻率的影响

采用电子辅助热丝化学气相沉积工艺, 在1kPa反应气压和施加不同的偏流条件下, 沉积了纳米金刚石薄膜. 用X射线衍射, 场发射扫描电镜和半导体特性表征系统对该薄膜进行了表征和分析. 结果表明, 施加偏流可以使薄膜晶粒呈现明显的(110)晶面择优取向, 表面形貌发生较大变化. 当偏流为8A时, 薄膜晶粒达到最小值, 约为20nm, 薄膜表面也最光滑. 本文讨论了在低气压和电子轰击条件下(110)晶面择优取向的形成机制及其对薄膜显微形貌和电阻率的影响关系.     

Basic properties of metal/insulator/semiconductor structures containing borazone and diamond layers produced by the reactive pulse plasma method

In this paper the results of an investigation of diamond and borazone layers produced by the reactive pulse plasma method on silicon substrates are presented. The properties of the layers were studied by conventional analysis of a metal/ insulator/semiconductor capacitor. The fundamental parameters (dielectric constant ε_ri of insulator, flat-band voltage U_FB, equivalent surface state density N_eff, interface trap density D_it and dielectric mobile charge density Q_m) of the structure were determined. The values of these parameters as well as the other structural and electrophysical properties of diamond and borazone layers, including their similarity to silicon, suggest possible applications of these layers in the technology of semiconductor devices. Nevertheless the exploitation of these advantages requires an improvement of the quality of the dielectric.     

The versatility of hot-filament activated chemical vapor deposition

In the field of activated chemical vapor deposition (CVD) of polycrystalline diamond films, hot-filament activation (HF-CVD) is widely used for applications where large deposition areas are needed or three-dimensional substrates have to be coated. We have developed processes for the deposition of conductive, boron-doped diamond films as well as for tribological crystalline diamond coatings on deposition areas up to 50 cm × 100 cm. Such multi-filament processes are used to produce diamond electrodes for advanced electrochemical processes or large batches of diamond-coated tools and parts, respectively. These processes demonstrate the high degree of uniformity and reproducibility of hot-filament CVD. The usability of hot-filament CVD for diamond deposition on three-dimensional substrates is well known for CVD diamond shaft tools. We also develop interior diamond coatings for drawing dies, nozzles, and thread guides.Hot-filament CVD also enables the deposition of diamond film modifications with tailored properties. In order to adjust the surface topography to specific applications, we apply processes for smooth, fine-grained or textured diamond films for cutting tools and tribological applications. Rough diamond is employed for grinding applications. Multilayers of fine-grained and coarse-grained diamond have been developed, showing increased shock resistance due to reduced crack propagation.Hot-filament CVD is also used for in situ deposition of carbide coatings and diamond-carbide composites, and the deposition of non-diamond, silicon-based films. These coatings are suitable as diffusion barriers and are also applied for adhesion and stress engineering and for semiconductor applications, respectively.