Thermal stability of magnetron sputtering amorphous carbon nitride films

Magnetron sputtered amorphous carbon nitride films were annealed at different temperatures (450-900°C) and time (30-120 min). Compositional, bonding structural and surface morphological modifications of the films were characterized by Fourier transformation infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy. The as-deposited film was found to have nitrogen content of 30 at%, and the carbon atoms were bonded to nitrogen atoms in the chemical structure state of CN, CN and CN bonds. The FTIR and XPS results showed that the films were thermally stable without an obvious change in the films as annealing temperature was lower than 600°C. The relative intensity ratio of CN over CN bonds reached a maximum at annealing temperature of 750°C, and then decreased gradually at annealing temperature up to 900°C. The CN bonds in the films decreased with the increase of annealing temperature and eliminated completely at annealing temperature of 900°C. These results revealed that annealing caused a substantial decrease in the number of weak bonds between carbon and nitride atoms. The CN bonds have higher thermal stability than CN bonds and CN bonds in the films. Simultaneously annealing also led to the formation of a large fraction graphitic-like carbon in the films while nitrogen escaped from the film. Besides, the surface roughness of the films increased with annealing temperature. However, when annealing time was increased from 30 to 120 min at annealing temperature of 750°C, only a slight effect of the annealing time on composition, bonding structure and the surface roughness of the films was observed.     

磁控溅射非晶CNx薄膜的热稳定性研究

为了研究非晶CNx薄膜的热稳定性,采用射频磁控溅射方法沉积了非晶CNx薄膜样品,并在真空中退火至900℃,利用FTIR,Raman和XPS谱探讨了高温退火对CNx薄膜化学成分及键合结构的影响.研究表明:CNx薄膜样品中N原子分别与sp、sp2和sp3杂化状态的C原子相结合,退火处理极大地影响了CN键合结构的稳定性;当退火温度低于600℃时,膜内N含量的损失较少,CNx薄膜的热稳定性较好,退火温度超过600℃时,将导致CNx膜中大多数C、N间的键合分离,造成N大量损失,膜的热稳定性下降;退火可促使膜内sp3型键向sp2型键转变,在膜中形成大量的sp2型C键,导致CNx膜的石墨化.     

非平衡磁控溅射类金刚石碳膜的性能

用非平衡磁控溅射的方法在室温下制备了光滑、均匀、致密的类金刚石(DLC)薄膜,分析和研究了DLC膜的形貌、结构和摩擦特性.结果表明,靶工作电流对DLC膜的沉积有重要的影响.随着工作电流的增大,薄膜的沉积速率增大,薄膜中sp3键的含量增加.薄膜的摩擦系数随着工作电流的增加略有增大,在摩擦的初始阶段,摩擦系数较高,随着摩擦循环次数的增加,摩擦系数逐渐减小,并逐渐趋于稳定.     

Crystallization of amorphous indium zinc oxide thin films produced by radio-frequency magnetron sputtering

In this work we studied indium zinc oxide (IZO) thin films deposited by r.f. magnetron sputtering at room temperature. The films were annealed at high temperature (1100 K) in vacuum, and the oxygen exodiffusion was monitored in-situ. The results showed three main peaks, one at approximately 600 K, other at approximately 850 K and the last one at 940 K, which are probably from oxygen bonded in the film surface and in the bulk, respectively. The initial amorphous structure becomes microcrystalline, according to the X-ray diffraction. The electrical conductivity of the films decreases (about 3 orders of magnitude), after the annealing treatment.This behavior could be explained by the crystallization of the structure, which affects the transport mechanism. Apart from the changes in the material structure, a small variation was observed on the absorption coefficient.     

反应RF磁控溅射法制备非晶氧化硅薄膜及其特性研究

在氧气和氩气的混合气体中,在没有额外加热的条件下用反应射（RF）溅射硅靶制备了非晶氧化硅（a-SiO2)薄膜,并测试分析了薄膜的结构和电特性与O2／Ar流量比的关系。当固定氩气流量,改变氧气流量时,薄膜沉积速率先急剧减少,再增大,然后又减少。当O2／Ar≥0．075时,得到满足化学配比的氧化硅薄膜。并且,随着O2／Ar流量比的增大,薄膜的电阻,电场击穿强度都有所增大,而在HF缓冲溶液（BHF）中的腐蚀速率下降,所有的样品中无明显的H－OH水分子的红外吸收峰。比较发现反应射频（RF）磁控溅射法制备的a-SiO2薄膜具有良好的致密性和绝缘性。     

Structural analysis of amorphous Si films prepared by magnetron sputtering

A study is presented on the structural changes occurring in thin amorphous silicon (a-Si) during thermal treatments. The a-Si films were deposited on single-crystalline Si substrates held at room temperature by magnetron sputtering of a Si target in pure Ar atmosphere, and therefore the films were hydrogen-free. All samples were annealed in vacuum and subsequently studied by electron paramagnetic resonance (EPR) and grazing incidence X-ray diffraction (GIXRD). A slight increase in the dangling bonds content at lower annealing temperatures, and then a strong increase of it at around 650 °C, suggested significant structural changes. The samples were also studied by grazing incidence small-angle X-ray scattering (GISAXS) which confirmed changes at the nanometric scale attributed to voids in the material. A nice correlation of the results of the three techniques shows advantages of this approach in the analysis of structural changes in a-Si material.     

Thermal stability of amorphous and crystalline multilayers produced by magnetron sputtering

For the demonstration of the high diversity of different applications of the magnetron sputtering technique in the fabrication of multilayers the production, characterisation and investigations on the thermal stability of epitaxial metallic Mo\V as well as amorphous Si\Ge semiconductor multilayers are presented. It is demonstrated, that combination of low and high angle X-ray diffraction as well as TEM is a very essential tool for the characterisation of the modulated structures and it is also very useful in the investigation of the thermal stability. The experimental results are also compared with numerical calculations made by finite element method for the diffusional homogenisation, controlled by bulk diffusion. It was shown, that in the case of the amorphous Si\Ge system the intermixing is possible in amorphous state, and diffusional stresses do not cause a significant curvature on the thermal decay curves of the first order peak of the low angle Bragg reflection (ln(I\I₀) vs t), but they play an important role in the strong porosity formation in the silicon side. Furthermore it was illustrated, that the initial curvature on the ln(I\I₀) vs t curve is due to the strong concentration dependence of the intrinsic diffusion coefficients. In epitaxial Mo\V multilayers the thermal behaviour is different. There is a fast transformation of the layered structure into a heterogeneous partly reacted structure, which consists of regions of a reacted Mo(V) alloy and the remaining Mo\V layers. This can not be interpreted by bulk diffusion, but rather by the formation of grain-boundaries inside the Mo layer and probably by a grain-boundary motion induced alloying.     

Substrate geometry effect on the uniformity of amorphous carbon films deposited by unbalanced magnetron sputtering

A chromium doped amorphous carbon (a-C) film was deposited by an unbalanced magnetron sputtering. A special designed double-V shaped stainless steel model in simulating a plastic injection mold gateway was used as the substrate to investigate the geometric effect on the uniformity of the film. It was found that, on both the side wall and bottom plane of the double-V shaped substrate, the film properties strongly depended on a geometric parameter, geometric aspect ratio, defined as the depth over width of the simulated gateway at the points under measurement. With the increase of the aspect ratio, i.e. approaching to the narrow end and/or closer to the bottom plane of the gateway, the film thickness and hardness decreased and the intensity ratio of the Raman sub-bands D over G increased. With the increase of the aspect ratio, the micro hardness of the a-C film decreased far more significantly on the side wall than that on the bottom plane. With increasing working gas pressure, the film thickness decreased consistently, and the hardness uniformity on both the side wall and bottom plane was improved. When the substrate negative bias voltage was changed from −70 to −100 V, the film uniformity (for both the thickness and hardness) was improved on the bottom plane, but degraded on the side wall.     

直流磁控溅射制备TiNxOy薄膜的性能研究

利用直流磁控溅射技术在玻璃衬底上制备了TiNxOy薄膜样品,研究了溅射过程中电压与N2流量之间的迟滞效应,通过X射线衍射（XRD）、UV-Vis分光光度计、四探针电阻仪等测试手段表征了样品的物相、光吸收谱、电阻等性能。结果表明：随着N2含量的提高和薄膜厚度的增加,XRD显示薄膜样品出现明显的衍射峰,吸收光谱向可见光方向展宽至500nm,电阻随着N2含量的提高呈逐渐下降的趋势。     

Chemical states of carbon in amorphous boron carbide thin films deposited by radio frequency magnetron sputtering

Boron carbide thin films were deposited by radio frequency (RF) magnetron sputtering and characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and high resolution transmission electron microscopy. The results reveal that the structure of thin films deposited at substrate temperatures lower than 350 °C is amorphous. We found that there are four chemical states for carbon in amorphous boron carbide thin films deposited by RF magnetron sputtering. One is the segregated carbon in form of the graphitic inclusions in the thin film identified by Raman spectroscopy and Raman mapping using two strong peaks at ~ 1360 cm^− 1 and ~ 1590 cm^− 1, but the XPS results show that the graphitic inclusions do not connect to the substrate directly. On the surface the carbon forms C=O bonds characterized by the peak of C1s core level at 285.0 eV besides B-C bonds in the boron carbide with the peak of C1s being at 282.8 eV. The detailed analysis of B-C bonds in the boron carbide shows that there are two states for carbon atoms in B-C bonds: in the C-B-C models with C1s peak at 282.3 eV and in the icosahedra with C1s peak at 283.3 eV.     

反应RF磁控溅射法制备非晶氧化硅薄膜及其特性研究

在氧气和氩气的混合气体中，在没有额外加热的条件下用反应射频（RF）溅射硅靶制备了非晶氧化硅(a-SiO     

Growth of thin Ag films produced by radio frequency magnetron sputtering

Thin Ag films in the thickness range D = 14–320 nm were deposited by radio frequency magnetron sputtering on glass substrates at room temperature inside a vacuum chamber with base pressure of about 5 × 10^− 6 Pa. The growth of the films was studied via X-ray diffraction and atomic force microscopy experiments. The two techniques are complementary and give us the opportunity to study the surface roughness, the statistical distribution and the average value of the grain size, as well as the texture of the samples. It is shown that the film roughness increases negligibly within the first 60 atomic layers of growth. The thicker films (D 300 nm) develop a nanocrystalline structure with a root mean square roughness of about 2.5 nm. The grain size evolves linearly with the thickness from 9.4 nm at D = 54 nm to 31.6 nm at D = 320 nm.     

Properties of tantalum oxynitride thin films produced by magnetron sputtering: The influence of processing parameters

The main purpose of this work is to present and to interpret the change of structure and physical properties of tantalum oxynitride (TaN_xO_y) thin films, produced by dc reactive magnetron sputtering, by varying the processing parameters. A set of TaN_xO_y films was prepared by varying the reactive gases flow rate, using a N₂/O₂ gas mixture with a concentration ratio of 17:3. The different films, obtained by this process, exhibited significant differences. The obtained composition and the interpretation of X-ray diffraction results, shows that, depending on the partial pressure of the reactive gases, the films are: essentially dark grey metallic, when the atomic ratio (N + O)/Ta < 0.1, evidencing a tetragonal β-Ta structure; grey-brownish, when 0.1 < (N + O)/Ta < 1, exhibiting a face-centred cubic (fcc) TaN-like structure; and transparent oxide-type, when (N + O)/Ta > 1, evidencing the existence of Ta₂O₅, but with an amorphous structure. These transparent films exhibit refractive indexes, in the visible region, always higher than 2.0.The wear resistance of the films is relatively good. The best behaviour was obtained for the films with (N + O)/Ta ≈ 0.5 and (N + O)/Ta ≈ 1.3.     

Properties of zirconia thin films prepared by reactive magnetron sputtering

The search for alternative dielectric materials with high dielectric constant, thermodynamic stable on silicon substrate and low direct tunneling current leads to oxide based materials like zirconia. Zirconia thin films were prepared by reactive magnetron sputtering. The capacitance voltage, ac and dc electrical characteristics were investigated and the values like fixed oxide charges were calculated and compared among the samples with and without annealing. Films annealed at 700 °C showed a dielectric constant ∼ 26 with interface trap densities of 1.629 × 10¹² eV^− 1 cm^− 2.     

射频磁控溅射制备硼碳氮薄膜

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N2)为工作气体,在Si (100)衬底上制备出硼碳氮薄膜.通过X射线衍射(XRD)、傅里叶红外吸收光谱(FTIR)和X射线光电子能谱(XPS)等分析手段对样品结构、组分进行了分析.结果表明,样品的组成原子之间实现了原子级化合,且薄膜为乱层石墨结构.样品中B、C、N的原子比近似为1:1:1.     

Fabrication of transparent conducting amorphous Zn-Sn-In-O thin films by direct current magnetron sputtering

Amorphous ZnO-SnO₂-In₂O₃ films were grown by direct current magnetron sputtering from vacuum hot pressed ceramic oxide targets of Zn:In:Sn cation ratios 1:2:1 and 1:2:1.5 onto glass substrates. X-ray diffraction analysis showed that the microstructure remained amorphous during annealing at 200 °C for up to 5 hours. By monitoring the electrical resistivity, oxygen content and substrate temperature were optimized during deposition. The optimal films were characterized by Hall Effect, work function and optical spectroscopy measurements. Films of 1:2:1 composition showed the lowest resistivity (7.6 × 10^− 4 Ω-cm), when deposited onto substrates preheated to 300 °C. Transmissivity of all films exceeded 80% in the visible spectral region. The energy gap was 3.52-3.74 eV, and the work function ranged 5.08-5.22 eV, suitable for cathode applications in organic light emitting diodes. Overall, the film characteristics were comparable or superior to those of amorphous tin-doped indium oxide and zinc-doped indium oxide films and may serve as viable, lower-cost alternatives.     

Properties of Al heavy-doped ZnO thin films by RF magnetron sputtering

Al-doped ZnO films were deposited by RF magnetron sputtering. From the X-ray diffraction and scanning electron spectrometer studies, wurtzite structure with (0 0 2) orientation ZnO thin films were obtained at Al concentration below 15 atomic percent (at.%). As the Al concentration above 15 at.%, the thin films did not fully crystallize. Two new emission peaks occurred at 351 nm and 313 nm when the Al doping above 15 at.% from the photoluminescence spectrum, and the peaks shift towards the shorter wavelengths with increasing the Al concentration. X-ray photonic spectra of O 1s conformed the amount of oxygen captured by Al³⁺ increasing as the Al³⁺ concentration increasing due to the dominant Al³⁺ possess high charge in competition with Zn²⁺ in the matrix of ZnO.     

Properties of TaSiN thin films deposited by reactive radio frequency magnetron sputtering

TaSiN is a promising material for application as electrically conductive diffusion barrier for the integration of high permittivity perovskite materials in integrated circuits. TaSiN thin films were deposited by reactive radio frequency magnetron sputtering using TaSi and TaSi_2.7 targets in an Ar/N₂ atmosphere. The sputter power was varied in order to achieve different TaSiN compositions. The stoichiometry of as-deposited films was estimated using Rutherford backscattering spectroscopy. The as-deposited TaSiN thin films are amorphous. Their crystallization temperature is above 700 °C and increases with higher nitrogen content. They have metallic conduction and ohmic behavior. The resistivity of as deposited films is in the range from 10^− 6 Ω m up to 10^− 3 Ω m and increases with nitrogen content. It was found that p⁺⁺-Si/Ta₂₁Si₅₇N₂₁ develops unacceptable high contact resistance. Introducing an intermediate Pt layer the stack p⁺⁺-Si/Pt/Ta₂₁Si₅₇N₂₁ had a good conductive properties and good thermal stability at 700 °C.