氟化非晶碳膜的微结构分析

利用等离子体增强化学气相沉积(PECVD)法,在不同的温度下制备了氟化非晶碳膜.采用原子力显微镜(AFM)、X 射线光电子能谱(XPS)和傅里叶红外吸收光谱(FTIR)等仪器对薄膜微结构进行了表征.研究发现,氟化非晶碳膜微观结构与薄膜生长过程温度控制密切相关,温度升高,膜内键合结构变化,sp2相对含量增加.     

氮掺杂氟化非晶碳薄膜光学性质的研究

用射频等离子体增强化学气相沉积(RF-PECVD)法制备氮掺杂氟化非晶碳(a-C:F:N)薄膜.用紫外-可见分光光谱仪、椭偏仪、傅立叶变换红外光谱仪对薄膜进行了检测.结果表明:随源气体中氮气含量的增加,光学带隙先减小后升高,折射率变化情况与之相反.在其它条件相同的情况下,升高沉积温度使得薄膜的光学带隙和折射率降低.光学带隙的大小与sp2键含量密切相关,sp2键浓度越大,薄膜的光学带隙越小.     

CF4,CH4制备氟化非晶碳薄膜工艺研究

以CF4和CH4为源气体,用等离子体增强化学气相沉积(PECVD)方法制备了不同工艺条件下的氟化非晶碳(a-C∶F)薄膜.发现薄膜的沉积速率和射频功率几乎成正比关系,薄膜中氟的存在是导致薄膜具有紫外吸收特性的根本原因;用傅立叶变换红外光谱(FTIR)分析可知薄膜中有C-F基团的存在,使得薄膜的介电常数降低;合理控制沉积条件,可获得理想的电介质薄膜.     

氟化非晶碳(a-C:F)薄膜的研究

氟化非晶碳(a-C：F)薄膜是一种电、光学新材料。介绍了它的制备方法，对其制备工艺作了较全面的探讨；分析了该膜制备方法和工艺参数对薄膜组分及化学键结构的影响；研完了该膜的电学、光学、热学、力学等物理性质及其在相关方面的应用，并对该膜的物理性质与制备工艺参数的关联作了详细的论述；指出介电常数和热稳定性的矛盾是阻碍该膜实用化的主要原因。     

低介电常数材料和氟化非晶碳薄膜的研究进展

目前微电子器件正经历着一场材料结构的变革.由于其特征尺寸进入100nm,由内部金属连线的电阻和线间绝缘介质层的电容构成的阻容延时已经成为限制器件性能的主要因素.用电阻更小的铜取代目前使用的铝作金属连线,用低介电常数(低K)材料取代二氧化硅作线间介质成为重要的、应用价值巨大的研究课题.着重叙述了具有低介电常数的氟化非晶碳薄膜的研究进展.     

反应溅射制备非晶Al2O3薄膜的介电特性

在氧气、氩气的混合气氛中，利用反应射频磁控溅射制备了厚度在１００到１０纳米的非晶氧化铝薄膜。通过Ａｌ－Ａｌ２Ｏ３－Ａｌ电容器研究了此非晶薄膜的介电性质。     

ECR-CVD制备氟化非晶碳低k介质薄膜

采用电子回旋共振等离子体化学气相沉积(ECR-CVD)方法,以C4F8和CH4为源气体在不同气体流量比R(R=[CH4]/{[CH4] [C4F8]})条件下成功地沉积了氟化非晶碳(a-C:F)低介电常数(低k)材料.采用X光电子能谱和椭圆光谱方法分析了a-C:F薄膜的化学组分和光学性质.沉积的a-C:F薄膜介电常数约为2.1～2.4,热稳定性优于350℃.随着气体流量比的增大,沉积a-C:F薄膜中的碳含量增大,CF、CF2、CF3含量减少,C-C交链成分增加,从而使得π-π(*)吸收增强,并引起薄膜光学带隙下降.氮气气氛下350℃温度退火后应力释放引起a-C:F薄膜厚度变化,变化量小于4%.450℃温度退火后,由于热分解作用薄膜厚度变化量在30%左右.     

ICP—CVD制备氟化非晶碳（a—C：F）薄膜的研究

本文使用CH2F2为源气体,利用电感耦合等离子体增强化学气相沉积(ICP-CVD)法在不同放电模式(连续或脉冲)、沉积气压、射频功率和位置下制备了a-C∶F薄膜.用原子力显微镜(AFM)观察了薄膜的表面形貌,通过FTIR、XPS对其结构进行了表征.研究结果表明:放电模式、放电气压、射频功率、基底位置均对薄膜的表面粗糙度(RMS)和组成具有重要的影响.在脉冲波模式下,增加放电气压,薄膜RMS值的变化呈现出先降低后升高的变化趋势;基底距离线圈的距离越远,所沉积薄膜的RMS值越小.而在连续波模式下,距离线圈较远的B、C位置薄膜的RMS值却相对较高.增加放电功率导致沉积薄膜的RMS值较小.本文也对CH2F2等离子体进行了发射光谱(OES)诊断研究.结果表明,对比脉冲波模式,连续波放电时等离子体中含碳物种明显减少.结合表征结果和OES结果对薄膜的生长机理进行了探讨.     

反应溅射制备非晶Al2O3薄膜的介电特性

在氧气、氩气的混合气氛中,利用反应射频磁控溅射制备了厚度在100到10纳米的非晶氧化铝薄膜.通过Al-Al2O3-Al电容器研究了此非晶薄膜的介电性质.     

氮气退火对氟化非晶碳膜结构和电学性能的影响

采用电子回旋共振等离子体化学气相淀积(ECR-CVD)方法以C4F8和CH4为源气体制备了氟化非晶碳(a-C:F)膜并在氮气气氛中对a-C:F膜进行了退火处理研究.X光电子能谱(XPS)化学结构分析表明,退火后a-C:F膜中CF3,CF2和CF含量减少,而C-CFx(x=1～3)交联结构增多.电学性能研究指出,退火后a-C:F薄膜的介电常数由于电子极化和薄膜密度的增大而上升,Al/a-C:F/Si结构的阻滞效应由于界面态密度下降而减弱,同时a-C:F膜的π-π*带隙和电荷陷阱能量减小并导致薄膜漏电流增大.     

氟化类金刚石膜结构、性能及应用

氟化类金刚石膜是基于传统类金刚石膜的基础上发展起来的一种改性材料,该膜具有许多良好的性能,包括疏水性能、电学性能、光学性能、机械性能、热稳定性以及生物相容性,因此引起了人们的极大关注.本文介绍了氟化类金刚石膜的结构、性能、应用领域和发展趋势.     

Annealing effects on structural and electrical properties of fluorinated amorphous carbon films deposited by plasma enhanced chemical vapor deposition

The annealing effects on the structural and electrical properties of fluorinated amorphous carbon (a-C:F) thin films prepared from C₆F₆ and Ar plasma are investigated in a N₂ environment at 200 mTorr. The a-C:F films deposited at room temperature are thermally stable up to 250 °C, but as the annealing temperature is increased beyond 300 °C, the fluorine incorporation in the film is reduced, and the degree of crosslinking and graphitization in the film appears to be enhanced. At the annealing temperature of 250 °C, the chemical bond structures of the film are unchanged noticeably, but the interface trapped charges between the film and the silicon substrate are reduced significantly. The increased annealing temperature contributes the decrease of both the interface charges and the effective charge density in the a-C:F film. Higher self-bias voltage is shown to reduce the charge density in the film.     

Effect of ambient gaseous environment on the properties of amorphous carbon thin films

Amorphous carbon films have been deposited by filtered cathodic jet carbon arc technique under different gaseous environments. Scanning electron microscope and atomic force microscope studies have been performed on the deposited films for the surface morphological studies. The morphology of the deposited film changes with the change in gas environment. X-ray photoelectron spectroscopic (XPS) and Raman studies have been carried out on the deposited samples for the evaluation of the chemical bonding of carbon atoms with the ambient gas atoms. The sp³ and sp² contents have been evaluated from the XPS studies and found to be dependent on the gaseous environment. The film deposited under hydrogen environment has the highest value of the sp³ content (54.6 at.%) whereas the film deposited under helium environment has the lowest value of sp³ content (37 at.%). For the evaluation of the electrical and mechanical properties of the deposited films, the electrical conductivity and nanoindentation measurements have been performed on the deposited films. It has been observed that the film deposited under helium environment has the highest electrical conductivity and the lowest hardness (∼15 GPa) value whereas film deposited under hydrogen environment has the highest hardness (∼21 GPa) and the lowest conductivity.     

Effect of nitrogen addition on the properties and thermal stability of fluorinated amorphous carbon films

Continuous fluorinated amorphous carbon (a-C : F) films doped with nitrogen (a-C : F : N) were deposited by plasma enhanced chemical vapor deposition using CF₄ and C₂H₂ gases as precursors with the addition of N₂ gas. The surface morphologies, chemical compositions, deposition rates, thermal stability and mechanical properties of these films varied with the deposition parameters, including CF₄ and N₂ feed gas concentrations, processing pressure, plasma power and substrate temperature. With increasing N₂ feed gas concentration, the nitrogen content of the a-C : F : N films increased to about 6 at.% and contributed to higher mechanical properties. After thermal annealing, the a-C : F films with higher fluorine contents exhibited more obvious fluorine release and extensive film thickness shrinkage, whereas the a-C : F : N films with higher contents of nitrogen doping yielded less composition variations, smaller thickness shrinkages, higher mechanical properties, and conclusively better thermal stability.     

Electrochemical corrosion behavior of amorphous carbon nitride thin films

The corrosion behavior along with biocompatibility and mechanical properties plays an important role in determining of biomedical implants feasibility. Diamond-like carbon seems to be the promising material in which all these three requirements can be achieved. In this study nitrogen doped amorphous carbon (a-C:N) films were deposited on silicon and medical CoCrMo alloy substrates by vacuum glow discharge sputtering technique using different deposition conditions from graphite target. Potentiodynamic polarization tests were employed to assess the corrosion performances of the films at room temperature in 0.89 wt. % NaCl solution. The influence of substrate bias on the electrochemical corrosion behavior was investigated. The highest value off E_corr for CoCrMo substrate was measured on the coating deposited with substrate bias around −0.6 kV. The shift of E_corr to more positive values was about 350 mV.     

ECR-CVD制备的SiOx/a-C:F/SiOx多层膜的结构与介电性质

使用80％Ar稀释的SiH4,O2,CHF3和CH4作为前驱气体,利肝微波电子回旋共振等离子体化学气相沉积(ECR-CVD)方法制备了SiOx／a-C：F／SiOx多层膜。傅里叶变换红外测试结果表明了多层膜中存在大量的C-F,C=C,Si-O键,同时由于器壁的吸附效应,膜中还存在少量的Si-C和Si-F键,这些键的存在从x射线光电子能谱的深层剖析结果得到了证实。热退火的结果表明了薄膜的红外结构没有发生太大的变化,薄膜的介电常数经过400℃的退火后仅上升了8％。实验结果表明了ECR-CVD制备的SiOx／a-C：F／SiOx多层膜可以成为超大规模集成电路中层间绝缘层的候选材料。     

Dielectric response and structure of amorphous hydrogenated carbon films with nitrogen admixture

The optical properties and structure of a-C:H films were modified by addition of nitrogen into the CH₄/H₂ deposition mixture. Three films prepared in capacitively coupled rf discharge were compared: (a) hydrogenated diamond like carbon film with hydrogen content of 34% and indentation hardness of 21.7 GPa, (b) hard a-C:H:N film with nitrogen content of 13% and indentation hardness of 18.5 GPa and (c) soft a-C:H:N film with nitrogen content of 10% and indentation hardness of 6.7 GPa. It is shown how the parametrized density of states model describing dielectric response of electronic interband transitions can be applied to modified a-C:H:N and how it can be combined with correct treatment of transmittance measured in infrared range using additional Gaussian peaks in joint density of phonon states. This analysis resulted in determination of film dielectric function in wide spectral range (0.045-30 eV) and provided also information about the density of states of valence and conduction bands and lattice vibrations.     

Surface adsorption and wetting properties of amorphous diamond-like carbon thin films for biomedical applications

Diamond-like carbon (DLC) thin films have unique properties for biological and medical applications due to their excellent bio-compatibility, chemical inertness, and superior mechanical properties. It is important to understand the surface properties of DLC thin films for these applications. In this work, we showed that after DLC deposition, NiTi surfaces became much smoother by choosing suitable deposition conditions. Adsorption and wetting properties of DLC films were studied. The adsorption properties of DLC films were unusual in that a hysteresis was found in the adsorption/desorption isotherms, which cannot be interpreted using the conventional theory of capillary condensation in pores. The model proposed in this work for this unusual hysteresis characteristic is that the hysteresis results from the non-wetting property of DLC surfaces in the nano-scale. The nano-sized droplets formed on the DLC surfaces may require significantly higher energy to evaporate than the formation energy. Argon plasma treatment resulted in a small decrease of the contact angles. After oxygen plasma treatment, the wetting contact angles reduced significantly due to the increase of carbon-oxygen sites on the surfaces, suggesting that the low concentration of carbon-oxygen sites on the surfaces of DLC films contributed to the adsorption hysteresis observed in this work.