离子的轰击对Si衬底上金刚石核附着力的影响

利用扫描电子显微镜和原子力显微镜对负衬底偏压增强金刚石核化的过程进行了分析,从理论上探索了负衬底偏压作用下离子的轰击效应增强金刚石核在Si衬底上附着力的机理,给出了金刚石核与衬底的附着力和衬底负偏压之间的关系.     

离子的轰击对Si衬底上金刚石核附着力的影响

利用扫描电子显微镜和原子力显微镜对负衬底偏压增强金刚石核化的过程进行了分析,从理论上探索了负衬底偏压作用下离子的轰击效应增强金刚石核在Si衬底上附着力的机理,给出了金刚石核与衬底的附着力和衬底负偏压之间的关系.     

化学气相沉积法制备金刚石膜截面微区Raman分析

采用微区Raman散射分析方法研究化学气相沉积法制备的金刚石膜的横截面.金刚石膜从衬底面到生长面不同位置具有不同特征的Raman谱,依此对膜中的金刚石、石墨和非晶碳成分进行分析.衬底面附近区域对应金刚石膜生长过程的成核阶段,非晶碳成分含量较高,相应于1200—1600cm^-1波段较大的散射强度和存在较强的荧光背底.膜厚增大,非晶碳成分中sp³结构成分首先减少,而sp²结构成分和石墨成分的减少相对缓慢.而生长面附近区域只有比较单纯的晶体金刚石 关键词：     

电子助进热丝化学汽相沉积金刚石薄膜

以CH₄和H₂为源反应气体，利用电子助进热丝化学汽相沉积（CVD）技术，在Si（100）晶面衬底上成功地得到了织构生长的金刚石薄膜．用扫描电子显微镜、Raman光谱、X射线衍射等多种技术对薄膜的形貌、成分、晶态等特性进行了分析，得到了在热丝CVD实验条件下织构生长金刚石薄膜的最佳工艺条件． 关键词：     

同质与异质外延掺杂CVD金刚石薄膜的结构与性能

采用化学气相沉积(CVD)技术,以高温高压(HTHP)合成的(100)金刚石和p型(100)Si为衬底制备了硫掺杂和硼-硫共掺杂金刚石薄膜,利用原子力显微镜(AFM)、扫描隧道显微镜(STM)及隧道电流谱(CITS)等手段分析同质和异质外延CVD掺杂金刚石薄膜的结构和性能.结果表明:异Si衬底上CVD金刚石的形核密度低,薄膜表面比较粗糙,粗糙度达到18.5nm;同质HTHP金刚石衬底上CVD金刚石薄膜晶粒尺寸约为10—50nm,表面平整,表面粗糙度为1.8nm.拉曼测试和电阻测量的结果显示,在HTHP金刚 关键词： 金刚石 掺杂 外延     

电子助进化学气相沉积金刚石中发射光谱的蒙特卡罗模拟

采用蒙特卡罗方法，对源料气体为CH4/H2混合气的电子助进化学气相沉积（EACVD）中 的氢原子(H)、碳原子(C)以及CH基团的发射过程进行了模拟.研究了CH4浓度、反应室气压 和衬底偏压等工艺参数对发射光谱及成膜的影响.研究发现，CH基团可能是有利于金刚石薄 膜生长的活性基团，而碳原子不是；偏压的升高可提高电子平均温度及衬底表面附近氢原子 的相对浓度；通过氢原子谱线可测定电子平均温度并找到最佳成膜实验条件.该结果对EACVD 生长金刚石薄膜过程中实时监测电子平均温度，有效控制工艺条件，生长出高质量的金刚石 薄膜具有重要的意义. 关键词： 蒙特卡罗模拟 金刚石薄膜 发射光谱     

电子增强化学气相沉积法制备金刚石膜

 采用EACVD方法在Si衬底上制备出生长速率高的优质金刚石膜，其生长速率最大可达7 μm/h，成膜范围Φ40 mm，并对优质金刚石膜的生长特性进行了研究。     

氮气氛下(100)织构金刚石薄膜的成核与生长研究

利用热丝化学气相沉积法研究了氮气浓度对金刚石薄膜成核和生长的影响.实验发现氮气的 加入对金刚石成核密度影响不大,但促进了已形成的金刚石核的长大.适量的氮气不仅使金 刚石生长速率得到很大的提高,而且稳定了金刚石薄膜(100)面的生长,使金刚石薄膜具有 更好的(100)织构.利用原位光发射谱对衬底附近的化学基团进行了研究.研究表明,氮气的 引入使得金刚石生长的气相化学和表面化学性质发生了很大变化.含氮基团的萃取作用提高 了金刚石表面氢原子的脱附速率,从而提高了金刚石膜的生长速率.而含氮基团的选择吸附 使金刚石 关键词： 氮气 金刚石薄膜 织构 原位光发射谱     

CVD金刚石膜的结构分析

利用x射线广角衍射和低角掠入射散射谱、正电子湮没谱、定性分析软件和Positronfit程序，研究了生长在Si（100）基底上的金刚石膜微结构.研究发现，在样品邻近基底区域为纳米 多晶结构，具有弱的［111］织构；在邻近表面区域为微米多晶结构，具有强的［220］织构 .金刚石膜样品有空位、空位团和空洞3种缺陷，其中主要缺陷是大约10个空位形成的空位团 . 关键词： 金刚石膜 化学气相沉积 x射线掠入射 正电子湮没谱     

p型半导体金刚石膜的磁阻效应

在p型硅(100)衬底上,采用衬底负偏压微波等离子体CVD方法进行了p型异质外延金刚石膜的生长.用O₂等离子体刻蚀技术将金刚石膜刻蚀成长条形,利用四探针法在0—5T的磁场范围内测量了样品的磁阻.实验结果表明,p型异质外延金刚石膜可以产生较大的磁阻.在Fuchs-Sondheimer(F-S)薄膜理论的基础上考虑晶格散射、杂质散射和表面散射,通过求解Boltzmann方程,利用并联电阻模型研究了p型异质外延金刚石膜的磁阻效应,给出了磁阻和金刚石膜厚度、迁移率、空穴密度及磁场的关系.讨论了表面散射和价带形变对p型异质外延金刚石膜磁阻的影响,初步解释了p型异质外延金刚石膜产生较大磁阻的原因 关键词： 金刚石膜 异质外延 磁阻效应 电导率     

Nucleation and initial growth of diamond by biased hot filament chemical vapour deposition

6 cm^-2 for non-scratched silicon. The maximum value of the nucleation density was over 10¹¹ cm^-2 on mirror-polished Si(100) at -300 V. The transportation process of the ion flux from the filament to the substrate is discussed in detail for biased substrates. The nucleation enhancement by the positive bias is believed to be a result of the increased impingement of the electrons emitted from the filament to the substrate surface. The studies have shown that electron emission from diamond plays a key role in negative-bias-enhanced nucleation by accelerating the dissociation of molecular hydrogen and hydrocarbon species into various free radicals and causing a plasma to be ignited near the substrate surface. The negative bias pretreatment is also a critical step in growing heteroepitaxial diamond films: the enlargement of the area of diamond clusters in contact with the substrate enhances the orientated growth of the films. Received: 18 October 1996/Accepted: 4 February 1997     

织构金刚石薄膜的成核与生长

在加衬底偏压和不加衬底偏压两种情况下，用微波等离子体化学汽相沉积（MWCVD）技术在Ｓｉ（１００）衬底上合成了织构的金刚石薄膜使用扫描电子显微镜（ＳＥＭ）和取向Ｘ射线衍射技术证实了我们得到的样品是织构的金刚石薄膜观察了织构的金刚石薄膜的成核和生长过程，从理论上对金刚石薄膜异质外延的成核和生长机理进行了探讨 关键词：     

富勒烯作为过渡层生长金刚石薄膜研究

采用微波等离子体化学气相淀积法，以Ｃ６０膜过渡层，在光滑的单晶Ｓｉ衬底（１００）表面的研磨的石英衬底表面等光学衬底上，首次在无衬底负偏压条件下生长出多晶金刚石薄膜，通过扫描电镜观察到生长膜晶粒呈莱花状，生长表面为金刚石（１００）界面。     

Effect of titanium powder assisted surface pretreatment process on the nucleation enhancement and surface roughness of ultrananocrystalline diamond thin films

A superior, easy and single-step titanium (Ti) powder assisted surface pretreatment process is demonstrated to enhance the diamond nucleation density of ultrananocrystalline diamond (UNCD) films. It is suggested that the Ti fragments attach to silicon (Si) surface form bond with carbon at a faster rate and therefore facilitates the diamond nucleation. The formation of smaller diamond clusters with higher nucleation density on Ti mixed nanodiamond powder pretreated Si substrate is found to be the main reason for smooth UNCD film surface in comparison to the conventional surface pretreatment by only nanodiamond powder ultrasonic process. The X-ray photoelectron spectroscopic study ascertains the absence of SiC on the Si surface, which suggests that the pits, defects and Ti fragments on the Si surface are the nucleation centers to diamond crystal formation. The glancing-incidence X-ray diffraction measurements from 100 nm thick UNCD films evidently show reflections from diamond crystal planes, suggesting it to be an alternative powerful technique to identify diamond phase of UNCD thin films in the absence of ultra-violet Raman spectroscopy, near-edge X-ray absorption fine structure and transmission electron microscopy techniques.     

大面积均匀纳米金刚石薄膜制备研究

报道了一种利用偏压恒流等离子辅助热丝化学气相沉积城硅基板上制备大面积均匀纳米金刚石薄膜的新工艺，在不同沉积条件下研究了纳米金刚石薄膜的成核和生长过程，并通过扫描电镜、拉曼光谱和表面粗糙度测试仪观察了纳米金刚石薄膜的结构特征。最后成功制备了直径100mm、平均晶粒尺寸10nm的光滑纳米金刚石薄膜。     

Optical and structural properties of polycrystalline CVD diamond films grown on fused silica optical fibres pre-treated by high-power sonication seeding

In this paper, the growth of polycrystalline chemical vapour deposition (CVD) diamond thin films on fused silica optical fibres has been investigated. The research results show that the effective substrate seeding process can lower defect nucleation, and it simultaneously increases surface encapsulation. However, the growth process on glass requires high seeding density. The effects of suspension type and ultrasonic power were the specific objects of investigation. In order to increase the diamond density, glass substrates were seeded using a high-power sonication process. The highest applied power of sonotrode reached 72 W during the performed experiments. The two, most common diamond seeding suspensions were used, i.e. detonation nanodiamond dispersed in (a) dimethyl sulfoxide and (b) deionised water. The CVD diamond nucleation and growth processes were performed using microwave plasma assisted chemical vapour deposition system. Next, the seeding efficiency was determined and compared using the numerical analysis of scanning electron microscopy images. The molecular composition of nucleated diamond was examined with micro-Raman spectroscopy. The sp³/sp² band ratio was calculated using Raman spectra deconvolution method. Thickness, roughness, and optical properties of the nanodiamond films in UV–vis wavelength range were investigated by means of spectroscopic ellipsometry. It has been demonstrated that the high-power sonication process can improve the seeding efficiency on glass substrates. However, it can also cause significant erosion defects at the fibre surface. We believe that the proposed growth method can be effectively applied to manufacture the novel optical fibre sensors. Due to high chemical and mechanical resistance of CVD diamond films, deposition of such films on the sensors is highly desirable. This method enables omitting the deposition of an additional adhesion interlayer at the glass–nanocrystalline interface, and thus potentially increases transmittance of the optical system.     

Growth of sputter-deposited Ni-Ti thin films: Effect of a SiO2 buffer layer

In-situ X-ray diffraction (XRD) during the growth of Ni-Ti thin films was chosen in order to investigate their texture development using a deposition chamber installed at a synchrotron radiation beamline. Near-equiatomic films were co-sputtered from Ni-Ti and Ti targets. The texture evolution during deposition is clearly affected by the substrate type and the ion bombardment of the growing film. On naturally oxidized Si(100) substrates, the Ni-Ti B2 phase starts by stacking onto (h00) planes, and as the thickness increases evolves into a (110) fibre texture. For the deposition on thermally oxidized Si(100) substrates, this pronounced cross-over is only observed when a substrate bias voltage (-45 V) is applied. The oxide layer plays an important role on the development of the (100) orientation of the B2 phase during deposition on heated substrates (≈470 °C). If this layer is not thick enough (naturally oxidized Si substrate) or if a bias voltage is applied, a cross-over and further development of the (110) fibre texture is observed, which is considered as an orientation that minimizes surface energies. Electrical resistivity measurements showed different behaviour during phase transformation for the Ni-Ti film deposited on thermally oxidized Si without bias and those on thermally oxidized Si(100) with bias and on naturally oxidized Si(100) without bias. This is related to stresses resultant from the fact that the Ni-Ti films are attached to the substrates as well as with the existence of distinct textures. PACS 81.15.Cd; 61.10.Nz; 68.55.Jk