Si(111) 衬底上3C-SiC的超低压低温外延生长

研究了发展一种Si衬底上低温外延生长3C－SiC的方法。采用LPCVD生长系统，以SiH4和C2H4为气源，在超低压（30Pa) ,低温（900℃）的条件下，在Si(111衬底上外延生长出高质量的3C－SiC薄膜材料。采用俄歇能谱（AES），X射线衍射（XRD）和原子力显微镜（AFM）等分析手段研究了SiC薄膜的外延层组分，晶体结构及其表面形貌。AES结果表明薄膜中的Si/C的原子比例符合SiC的理想化学计量比，XRD结果显示了3C－SiC外延薄膜的良好晶体结构，AFM揭示了3C－SiC薄膜的良好的表面形貌。     

Si(001)衬底上方形3 C-SiC岛的LPCVD生长

Si衬底上SiC的异质外延生长深受关注,为了了解Si衬底上的成核及长大过程,采用PLCVD方法在Si(001)衬底上生长出了方形3C-SiC岛,利用Nomarski光学显微镜和扫描电子显微镜（SEM）观察了SiC岛的形状,尺寸,密度和界面形貌,结果表明,3C－SiC岛生长所需的Si原子来自反应气源,衬底上的Si原子不发生迁移或外扩散,气相中C原子浓度决定了SiC岛的生长过程。     

Si(111)衬底上多层石墨烯薄膜的外延生长

利用固源分子束外延(SSMBE)技术, 在Si(111)衬底上沉积碳原子外延生长石墨烯薄膜, 通过反射式高能电子衍射(RHEED)、红外吸收谱(FTIR)、拉曼光谱(RAMAN)和X射线吸收精细结构谱(NEXAFS)等手段对不同衬底温度(400、600、700、800℃)生长的薄膜进行结构表征. RAMAN和NEXAFS结果表明: 在800℃下制备的薄膜具有石墨烯的特征, 而 400、600和700℃生长的样品为非晶或多晶碳薄膜. RHEED和FTIR结果表明, 沉积温度在600℃以下时C原子和衬底Si原子没有成键, 而衬底温度提升到700℃以上, 沉积的C原子会先和衬底Si原子反应形成SiC缓冲层, 且在800℃沉积时缓冲层质量较好. 因此在Si衬底上制备石墨烯薄膜需要较高的衬底温度和高质量的SiC缓冲层.     

Si(111)衬底上HVPE GaN厚膜生长

在Si(111)衬底上,以MOCVD方法高温外延生长的AIN为缓冲层,使用氮化物气相外延(HVPE)方法外延生长了15Km的c面GaN厚膜.并利用X射线衍射(XRD)、光致发光谱(PL)、拉曼光谱(Raman)等技术研究了GaN厚膜的结构和光学性质.分析结果表明,GaN厚膜具有六方纤锌矿结构,外延层中存在的张应力较小,...     

“第5届欧洲SiC及相关材料会议”——重点讨论衬底和外延生长

在意大利召开的(2004年)第5届欧洲SiC及相关材料会议(ECSCRM)的重点是：消除SiC衬底中的微管道，实时改变生长条件以降低GaN／Si异质结中的应变，在Si衬底上生长立方SiC。     

Si基β-SiC薄膜外延生长技术研究

采用SiH4-C3H8-H2气体反应体系,通过常压化学气相淀积（APCVD）工艺在P型Si(100)衬底上进行了β-SiC薄膜异质外延生长。利用俄歇电子能谱、SEM及X射线衍射能谱进行了生长薄膜微结构分析。提出并讨论了外延生长β－SiC薄膜的最佳工艺条件及其生长机理。     

锰及其硅化物在Si(100)表面的反应外延生长

采用超高真空分子束外延-扫描隧道显微镜(UHVMBE-STM)系统研究了不同温度下锰及其硅化物在Si(100)-2 ×1重构表面上的外延生长情况.实验结果表明当生长过程中衬底温度控制在室温到135℃时,生成大小基本一致的锰纳米团簇;当衬底温度达到210℃时锰与硅开始发生反应,形成硅化物,并有纳米线结构出现;当衬底温度达到330℃时,纳米线完全被棒状物或不规则的三维岛状硅化物取代.随着沉积时衬底温度升高,生成物的成核密度与生长温度的关系与经典的二维岛成核理论相符合.     

半导体SiC材料的外延生长

ＳｉＣ具有禁带宽度大、热导率高、电子的饱和漂移速度大、临界击穿电场高和介电常数低等特点，在高频、大功率、耐高温、抗辐照的半导体器件及紫外探测器和短波发光二极管等方面具有广泛的应用前景。本文简要介绍ＳｉＣ半导体材料的液相外延、化学气相和分子束外延生长的概况及生长过程中杂质的控制。     

Evolution of Si (and SiC) nanocrystal precipitation in SiC matrix

Si_1−xC_x films with varying ratio of carbon to silicon (C/Si) were fabricated by magnetron co-sputtering from a combined C and Si target. The composition in films was changed by adjusting the ratio of sputtered target's area between C and Si. Analysis of X-ray photoelectron spectroscopy for as-deposited films shows that C/Si atomic ratios of our films have ranges of 0.33-1.02. Thermal annealing of as-deposited films was carried out at various temperatures from 800 to 1100 °C in a conventional furnace. Fourier transform infrared spectra show a shift of Si-C stretching peak towards higher wavenumbers from ∼ 737 cm^− 1 to ∼ 800 cm^− 1 with increasing annealing temperature. From the results of Raman spectroscopy, X-ray diffraction and transmission electron microscopy, it was found that the dominant type of nanocrystals changes from Si to SiC in the films annealed at 1100 °C when the C/Si atomic ratio increases from 0.33 to 1.02.     

Black SiC formation induced by Si overlayer deposition and subsequent plasma etching

Black SiC formation by plasma etching with SF₆/O₂ chemistry is reported. Black SiC was produced by depositing Si overlayer on SiC and then etching the Si/SiC stack sequentially, thus replicating the black Si morphology to SiC. Black SiC is obtained with almost zero reflectance over the wavelengths from 300 nm to 1050 nm. Thicker Si film was advantageous, and it was important to optimize the etch condition considering both the black Si morphology and the flattening effect of SiC.     

在硅和硬质合金基体上金刚石薄膜生长研究

在硅和硬质合金基体上，用热丝CVD法生长出金刚石薄膜。利用X衍射、拉曼谱和扫描电镜对金刚石薄膜的结构形貌进行了检测，并与天然金刚石对比分析。     

Surface morphology control of the SiC (0001) substrate during the graphene growth

Abstract

The dependence of surface morphology of the SiC(0001) substrate on the rate with which it is heated up to the temperature of graphene growth was studied by three techniques: atomic force microscopy, Raman spectroscopy and Kelvin probe force microscopy. The study was carried out for the rates of substrates heating ranging from 100?°C/min to 320?°C/min. As a result, it was found out that both the width of the terraces forming on the surface of SiC substrate and the uniformity of the graphene layers covering these terraces significantly depend on the applied rate of the heating. It was also shown that the most homogeneous monolayer graphene with the minimum of double-layers inclusions is formed if the rate of SiC heating is about 250?°C/min.     

脉冲激光法外延生长锰氧化物薄膜

利用脉冲激光法在ＬａＡｌＯ３衬底上外延生长了Ｌａ－Ｃａ－Ｍｎ－Ｏ、Ｌａ－Ｓｒ－Ｍｎ－Ｏ等巨磁电阻薄膜,测定了这些薄膜电阻－温度特性,观测到了其铁磁转变及巨磁电阻效应,实验发现,较高的淀积温度使薄膜的峰值转变温度Ｔｐ降低,峰值电阻率增大,而高温后退火则具有相反的效果,分析比较了多种因素对薄膜生长与性能的影响及其机理。     

Electrical properties of Schottky diode Pt/SiC and Pt/porous SiC performed on highly resistif p-type 6H-SiC

We investigated the electrical characteristics of two different Schottky diode as Pt/SiC and Pt/porous SiC, elaborated on highly resistif hot-pressed p-type 6H-SiC supplied by Goodfellow. The Schottky diode was characterized in air ambient and in vacuum, this latter could be used for exhaust gas monitoring as gas sensors for different gas (O₂, H₂, CO, CO₂ and hydrocarbure). The result shows an ideality factor in range 1.1-1.5 with a barrier height varying between 0.780 and 0.950 eV function of the ambient characterization. The result indicated clearly the dependence of electrical parameters on the surface whose Schottky contact was realized (Pt) and on the ambient where the electrical tests were performed.     

碳化硅质焊料连接氮化硅/碳化硅陶瓷的性能研究

采用以碳化硅为主相的焊料,在无压的条件下,连接氮化硅结合碳化硅陶瓷.结果表明:焊料在室温到1323K的干燥和烧结过程中,体积稳定,稍有膨胀.在1173K保温3h的条件下,连接的样品拉伸强度达到1.76MPa,热震残余强度保持率为82%.接头致密,并且焊料层与母材显微结构非常相似,界面处有明显的元素扩散,这对于提高结合强度和热震性能有重要作用.     

Investigation of the nucleation and growth of SiC nanostructures on Si

Using in situ reflection high energy electron diffraction (RHEED), ex situ atomic force microscopy (AFM) and transmission electron microscopy (TEM) the early stages of SiC growth on Si during the carbonisation were investigated in a solid source molecular beam epitaxy equipment. Different mechanisms of SiC precipitate growth by SSMBE were found. The SiC growth during carbonisation of Si(111) at 600°C is controlled by diffusion and at higher temperatures by a two-dimensional nucleation process, which is mononuclear at 660°C and polynuclear above 750°C. At temperatures greater than 750°C and 850°C three-dimensional nucleation occurs at (111) and (100) surfaces, respectively.