Sputtering Characteristics Research Articles

An ion-beam surface sputtering approach to the quest for lead-free metal halide perovskite for solar cells

Abstract Metal halide perovskites have been the subject of intense theoretical and experimental research in recent years, due to their huge potential over their silicon-based counterparts for tunable optoelectronic applications in high-tech device innovation. The current best perovskite for solar cell applications, with a power conversion efficiency of 22%, methylammonium lead iodide (CH3NH3PbI3), is toxic due to the presence of lead and is therefore harmful in solar cell applications despite its low concentration in solar cells. Hence, research exploits are geared towards perovskites without lead. Unfortunately, this has taken back the gains in PCEs by about 70%, and a lot is being done for improvement. In this paper, a new approach to these studies is introduced by performing Monte Carlo simulations of ion-beam sputtering of lead and tin perovskites, as well as other promising candidate materials, in order to throw some light on their potentials for higher efficiencies in photovoltaic applications. The sputtering characteristics of six promising perovskites, including lead perovskite and lead-substituted perovskites, were compared. The results showed a remarkable exhibition of similar sputtering characteristics of linear projected ion range for Pb and Sn, with a maximum sputter yield around 78° ion incidence. The results also indicated a correspondence between the sputtering characteristics and PCE.

Projected Range and Sputter Yield of Ne+ and Ar+ in the Sputtering of Lead and Tin Perovskites

Metal halide perovskites have been the subject of intense theoretical and experimental research in recent years due to their huge potential over their silicon based counterparts for tunable optoelectronic applications in high-tech device innovation. The current best perovskite for solar cell applications, with a power conversion efficiency of 22%, methyl ammonium lead iodide (CH3NH3PbI3), is toxic due to the presence of lead and is therefore harmful in solar cell applications despite its low concentration in solar cells. Hence, research exploits are geared towards perovskites without lead. Unfortunately, this has taken back the gains in PCEs by about 15%, and a lot is being done for improvement. In this paper, we performed molecular dynamics and Monte Carlo simulations of ion-beam sputtering of lead and tin perovskites to determine differences between the sputtering characteristics of lead perovskite and a lead-substituted perovskite (tin perovskite). Our results show that they both exhibit similar sputtering characteristics of linear projected ion range, and maximum yield around 78° ion incidence.

Zr-O-N coatings for decorative purposes: Study of the system stability by exploration of the deposition parameter space

The deposition of decorative coatings is an excellent solution to modify the surface of any material, particularly the aesthetic finishing, without altering the properties of the substrate. Transition metal oxynitride films are interesting for many applications, due the simple and economic way to tune between nitride and oxide bonding. In reactive sputtering, this is done by playing with the flows of N2 and O2, leading to variations of properties (e.g. color) in different directions. In this paper, zirconium is selected as transition metal due to the combination of different characteristics (color, biocompatibility, mechanical properties, corrosion resistance).The literature about Zr-O-N films reveals a confinement of chemical composition. Therefore, the aim of this work is the exploration of the deposition parameter space in order to evaluate the stability of the Zr-O-N system, i.e. verify if the chemical composition of the films still falls in the same range after variation of different deposition parameters. To do that, a series of Zr-O-N films is deposited first at different reactive flows, maintaining the remaining deposition parameters constant. The obtained films can be classified in three different groups, based on their chemical composition, crystalline structure, and film growth. These groups can be successfully explained according to the sputtering characteristics, and correlated with the mechanical properties and color of the films measured by nanoindentation and spectrophotometry respectively. The films deposited by variation of other parameters are introduced afterwards and their characteristics are compared with the reference series.

Features Multilevel Metallization Forming a Submicron Structures of Large Integrated Circuits

This paper analyzesaluminum alloys that are used to form multilevel metallization in the submicron LSI/VLSI and magnetic alloys that are used for the production of magnetic disks of external storage devices with a large amount of memory. In addition characteristics of magnetron sputtering devices that can be used to form thinmetallization are given: magnetron sputtering device with a magnetic block rotated by cooling deionized water, which can significantly increase the effectiveness of sputtering; high-frequency magnetron device UMV 2,5 with magnetic system that formed on electromagnets with scanning magnetic field; magnetron sputtering device UVN MDE.P-1250-012 which can be used to form double-sided metallization; magnetron sputtering device based on URM.3.279.05 which can be used to form multilayer contact metallization.

Influence of surface corrugation on the sputtering of carbon materials under high-fluence ion bombardment

The results of experimental and computer-based studies of the sputtering and erosion of carbonmaterial surfaces under high-fluence irradiation with 30-keV Ar+ ions at various angles of ion incidence are given. The irradiation of highly oriented pyrolytic graphite (HOPG) and polyacrylonitrile fibers of carbon–carbon composites, which are characterized by surface corrugation, is considered. A model is proposed for taking into account the influence of parameters of symmetric corrugation on the characteristics of sputtering of the irradiated materials. Calculation shows that taking experimental values of the corrugation slopes into account allows one to explain the angular dependence of the sputtering yield of HOPG. It is found that the pronounced (about two times) suppression of sputtering within the range of incidence angles of 60°–80° is connected with the rear (relative to the ion beam) faces of the corrugation being obscured. Unlike the case of the normal incidence of ions, the sputtering yield at large incidence angles decreases as the corrugation period increases due to blocking of the sputtering of the rear and neighboring faces of microrelief elements.

The effect of surface treatment of ceramic oxide coatings deposited by magnetron sputtering method on the adhesive and proliferative activity of mesenchymal stem cells

Abstract During the last years the interest to mesenchymal stem cells (MSCs) has significantly increased due to diverse clinical application of MSCs. As a result, it appears necessary to develop methods to increase the number of MSCs by culturing bone marrow (BM) cells in vitro, mainly to achieve consistent control of cell adhesion and proliferation processes at the biomaterial interface. In this study, we have analyzed the effect of surface treatment by argon ions bombardment and the electron beam irradiation on the structural and surface properties of the ceramic Al2O3 coatings by TEM, SEM and AFM methods. The coatings were deposited by reactive magnetron sputtering and surface characteristics were correlated with cultured MSCs adhesion. Finally, it could be shown that after electron beam irradiation Al2O3 coatings increased the adhesive and proliferative potential of MSCs compared to as-deposited oxide coatings.

Investigation of Al–Cr alloy targets sintered by various powder metallurgy methods and their particle generation behaviors in sputtering process

Al–Cr–N films for tribological application are commonly prepared by sputtering on Al–Cr alloy targets in an Ar + N2 mixed atmosphere. Generally, a film is manufactured by co-sputtering on an Al and Cr target, which tends to produce an arbitrary composition. It is difficult to produce an alloy target with a high Al ratio by melting technology due to the formation of brittle intermetallic compound phases (IMCs). In this study, alloy targets were manufactured by various powder metallurgy methods, included hot pressing (HP), hot isostatic pressing (HIP), and low temperature novel forming (LTNF). The results showed that at higher temperature, HP targets were dense and developed a large amount of IMCs, giving the target poor mechanical properties. Cracking tended to occur on the target surface, and many particles were generated during the sputtering process. At a lower temperature, IMC formation was inhibited in these targets, but the density was poor. The HIP method produced similar results to those of HP. LTNF was developed to achieve a dense target free of IMCs. Furthermore, the sputtering performances of the alloy targets were verified. For the LTNF target, almost no arcing count was recorded, fewer particles were generated and better film uniformity was obtained. The target and sputtering characteristics of conventionally-made (HP and HIP) methods were less desirable.

Study of carbon transport in the scrape-off layer of HL-2A with impurity sources located at limiter, dome, and divertor

Impurity transport in the scrape-off layer (SOL) has been studied in ohmically heated discharges of the HL-2A tokamak based on space-resolved vacuum ultraviolet spectroscopy. The vertical profile (from the plasma center to the lower X-point) of carbon emissions of CIII (977 Å: 2s2 1S0-2s2p ) and CIV (1548 Å: 2s 2S-2p 2P) as well as the ratio of CIV to CIII were measured to investigate the edge impurity transport with relation to impurity source locations and sputtering characteristics. The experimental result shows that the impurity profile in the SOL has been clearly changed against different source locations. The emission of CIII and CIV from the mid-plane is stronger than that from the X-point when the impurity source is located at the divertor plate. The profile becomes flat as a result. When the impurity source changes to the dome source, the profile clearly changes to a slightly peaked one, indicating the edge carbon emission at the X-point is stronger than the mid-plane. The change to the limiter source makes the profile further peaked by increasing the carbon emission at the X-point. In the case of the dome impurity source, the intensity of CIII/ne and CIV/ne, normalized to line-averaged electron density, ne, decreases with ne at low ne (ne ⩽ 2.6 × 1019 m−3) and becomes saturated at high ne (ne > 2.6 × 1019 m−3). In contrast, the ratio of CIV to CIII increases with ne at low ne and starts to decrease at high ne. A numerical simulation with 3D edge plasma transport code, EMC3-EIRENE, suggests that a poloidal asymmetry in the impurity flow profile and an enhanced physical sputtering play an important role in the edge impurity distribution, particularly in the screening efficiency of C2+ and C3+ ions in the SOL region of the HL-2A tokamak.

High-rate sputtering deposition of high- and low-refractive index films from conductive composites

Abstract

Conductive ZnO:Zn Composites for High-Rate Sputtering Deposition of ZnO Thin Films

We report an electrically conductive composite prepared by sintering ZnO and metallic Zn powders. Microstructure analysis combined with electrical conductivity studies indicated that when the proportion of metallic Zn reached a threshold (∼20 wt.%), a metal matrix was formed in accordance with percolation theory. This composite has potential as a sputtering target for deposition of high-quality ZnO. Use of the ZnO:Zn composite completely eliminates target poisoning effects in reactive sputtering of the metal, and enables deposition of thin ZnO films at rates much higher than those obtained by sputtering of pure ZnO ceramic targets. The optical transmittance of the ZnO films prepared by use of this composite is comparable with that of films produced by radio frequency sputtering of pure ZnO ceramic targets. The sputtering characteristics of the conductive ZnO:Zn composite target are reported, and possible mechanisms of the high rate of deposition are also discussed.

Stability of Amorphous in-Ga-Zn-O Thin Film Transistors with Silicon-Doped Back-Channel Layer under Temperature Humidity Stresses

In recent years, a-In-Ga-Zn-O thin film transistor has gained wide attention due to their good uniformity, high field-effect mobility and low cost process.[1-2] Although a -IGZO TFT has high device performance, it is certainly necessary to obtain the device stability under high temperature-relative humidity. The improvement of device stability under external environments is considered to be an important subject for the development of a-IGZO TFTs.To improve the a-IGZO TFTs characteristic and stability, the double active layer with a-IGZO/a-SIGZO was invested. The TFTs have an inverted staggered bottom gate structure with a channel width (W) of 500 µm and a channel length (L) of 50 µm. A 60 nm thick double active layer is grown by sputtering at room temperature, which contains 40 nm thick front-channel of a-IGZO and 20 nm thick back-channel with a-SIGZO by using cosputtering a-IGZO target and SiOx target at room temperature. Si concentration is changed with the rf power which split into 30, 40, 50, and 60 W.Figure 1 shows the transfer curves of the TFTs with various Si concentrations in a-SIGZO channel layer. As increasing Si concentration in back-channel, the IDS is lowered and the Vth shifted in the negative direction. The electrical properties reveal that Si is acting as a carrier suppressor due to reducing VO in the a-IGZO system. The bonding-strengths of silicon (775KJ/mol) is higher than those of zinc (385KJ/mol), and indium (<470KJ/mol).[3] Figure 2(a) shows that the Vth of the conventional a-IGZO TFT was negatively shifted from 26.7 to 21.4 V. The H2O molecules was adsorbed on the a-IGZO from the high humidity conditions lead to the decrease of the Vth . It may be attributed by the increase of carrier density in the a-IGZO bulk-channel due to the role of H2O molecules as donor. Compared to the conventional a-IGZO TFT, there are almost no difference on the Vth value between as-deposited sample and that of after 15 days, as shown in Fig. 2(b). The maximum and minimum of Vth are 30.7 and 29.6 V, respectively. It is reasonable that Si-metal cation suppress the formation of VO during the stability test. Additionally, SiO2 distributed on the a-IGZO surface reduce H2O adsorption site on a-IGZO back-channel surface.[4] As a result, the TFTs with a Si-doped a-IGZO back-channel improve the electrical stability under temperature and relative humidity stressesIn our presentation, we will review the mechanism why the co-deposition of SiOx enhance the stability of a-IGZO TFT by analyzing the standard electric potential (SEP) and bonding strengths of Si.* This work was financially supported by the Industrial Strategic Technology Development Program (10039191, The Next Generation MLC PRAM, 3D ReRAM, Device, Materials and Micro Fabrication Technology Development) funded by the Ministry of Trade, Industry and Energy (MOTIE), Korea. Reference [1] K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano and H. Hosono: Nature 432 (2004) 488.[2] M. K. Ryu, S. H. Yang, S. H. Park, C. S. Hwang: Appl. Phys. Lett. 95 (2009) 0173508.[3] J. K. Jeong, H. W. Yang, J. H. Jeong, Y. G. Mo, and H. D. Kim: Appl. Phys. Lett. 93 (2008) 123508.[4] S. H. Yang, K. H. Ji, U. K. Kim, C. S. Hwang, S. H. K. Park, C. S. Hwang, J. Jang, and J. K. Jeong: Appl. Phys. Lett. 99 (2011) 102103.Fig. 1. (a) The representative transfer characteristics of various sputtering powers of TFTs and (b) extracted subthreshold swing (S.S.), mobility and threshold voltage with various Si concentrations.Fig. 2. Evolution of the transfer characteristics for (a) conventional a-IGZO TFT, (b) a-SIGZO / a-IGZO TFT, and (c) variation in Vth for different active layered TFTs as a function of high temperature and relative humidity exposure.

Enhanced surface hardening of AISI D2 steel by atomic attrition during ion nitriding

An experimental study was conducted in order to investigate the surface hardness enhancement of AISI D2 steel, by ion nitriding through atomic attrition. Following a conventional ion nitriding process of 120min under an atmosphere of H2 and N2, an atomic attrition process was applied to the surface of AISI D2 steel under a gas mixture of Ar and N2 for 360min. A conventional ion nitriding of 480min was also performed for the purposes of comparison. The results obtained demonstrate that the surface hardness of AISI D2 steel undergoing ion nitriding and atomic attrition was about 1500HV; which is the highest surface hardness among all the specimens tested, and almost 250HV higher than that of a conventionally ion nitrided specimen. After nitriding by atomic attrition, those grains located along grain boundaries and in the vicinity of precipitates in the surface region were recrystallized, which is believed to be caused by the stress field formed between grains and different phases. In addition, the specimen that was ion-nitrided by atomic attrition exhibited a higher nitrogen concentration and a consequently greater quantity of chromium nitrides at the surface region, when compared to a single nitrided specimen. This could be attributed to the sputtering characteristics of argon in the plasma nitriding. The refined grains, higher nitrogen concentration, and greater amount of chromium nitrides all represent significant factors in the enhanced surface hardening of AISI D2 steel.

Effect of duty cycles on the deposition and characteristics of high power impulse magnetron sputtering deposited TiN thin films

High power impulse magnetron sputtering (HiPIMS) is a novel physical vapor deposition (PVD) technique. HiPIMS is a low-temperature process, giving well-adherent coatings, better quality films, and droplet-free deposition. It provides enhanced gas dissociation and highly ionized plasma by inputting a high power during short pulses to the target. The target material is therefore not only sputtered but also ionized during the deposition process. In this study, TiN thin films were deposited using a uni-polar mode HiPIMS process. Nitrogen was used as the reactive gas to deposit TiN along with Ar gas. The deposition of TiN films was investigated by varying the duty cycles from 2 to 10% to have peak power density ranging from 208 to 1064W/cm2. A high peak power density was obtained at a low duty cycle. DC magnetron sputtered TiN thin film (duty cycle=100%) was also deposited for comparison. We demonstrate that the HiPIMS deposited TiN thin film exhibits a denser structure and smoother surface at low duty cycles. It was also found that the intense ion bombardment at low duty cycles deteriorates the film structure and their mechanical properties. Moderate ion bombardment at a duty cycle of 4.5% gives the highest (111)/(200) intensity ratio and the highest amount of TiN bonding. This results in a film having the highest hardness, elastic modulus, and corrosion resistance of 29.3GPa, 388.2GPa, and 1.56E+06 (Ω/cm2), respectively. However, oxygen was found in the resulting films.

Определение характеристик распыления электролитического покрытия Ni-P с использованием атомно-эмиссионного спектрометра с тлеющим разрядом GDS 850 A

Conducted a review of the literature regarding the determination of cathodic sputtering rate for Ni-P coating and investigation of crater shape produced as a result of result of cathode etching in glow discharge lamp. The values of coating sputtering rate, main methods for determining the sputtering rate and its factors as well as the techniques of investigation into the ion etching crater shape depending on the parameters of the glow discharge were presented. During the research of the sputtering characteristics, the samples of Ni-P electrolytic coating on conducting substrate from 29 NK-alloy were made. Using the X-Ray electron-probe microanalysis the uniformity of chemical composition was studied. By utilizing a glow discharge atomic-emission spectrometer “GDS850 A” on the coating material the craters were obtained at different values of amperage and DC discharge voltage (gas pressure is constant). Craters were studied by mechanical profilometer with a diamond needle. As a result, a new quantitative method for classifying the deviation from the plane of the bottom of the crater was suggested. Optimum operating conditions for flat-bottomed craters at different operating conditions of the analysis were selected. In addition, the sputtering rate of the coating material was determined by weighing and measuring the volume of the crater. It is noted that the weighing method has significantly higher error and does not take into account the features of the sputtering material. Sputtering rate values that were obtained by using the volume crater method are comparable to the data described in the scientific literature. Defined sputtering rate values for Ni-P coating with respect to the substrate material. These values correlate well with the data presented by the developer of standard samples for the stratified analysis. Key words : glow discharge, direct current, sputtering rate, nickel-phosphorus, crater shape, atomic-emission spectrometry (Russian) DOI: http://dx.doi.org/10.15826/analitika.2014.18.1.005 A.L. Chicherskaya, A.A. Pupyshev Ural Federal University named after the first President of Russia B. N. Yeltsin , Ekaterinburg, Russia Federation

Effect of Sputtering Pressure On the Electrical Characteristics of RF Magnetron Sputtering Processed Zinc Tin Oxide Thin Film Transistors

not Available.

Surface Modification of Poly(methyl methacrylate) by Hydrogen-Plasma Exposure and Its Sputtering Characteristics by Ultraviolet Light Irradiation

Surface modification of poly(methyl methacrylate) (PMMA) films by hydrogen-plasma exposure has been studied in the light of sputtering resistance of polymer-based materials in plasma etching processes. Surface measurements of PMMA were performed with X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and spectroscopic ellipsometry. It has been found that oxygen atoms are preferentially removed from the surface when a PMMA film is subjected to hydrogen-plasma exposure, with the depth of modification being about 40 nm in the case we examined. Hydrogen-plasma exposure is also found to reduce the sputtering yields of PMMA by ultraviolet light irradiation, as in the case of Ar+ ion irradiation [S. Yoshimura et al.: J. Vac. Soc. Jpn. 56 (2013) 129]. The results suggest that PMMA films become hardened and more sputtering resistant due to the formation of a thick (i.e., 40 nm in the case of this study) amorphous carbon layer by hydrogen-plasma exposure. Hydrogen-plasma exposure is thus an effective technique to increase etching resistance of polymer films.

Industrial-scale sputter deposition of Cr1−xAlxN coatings with 0.21 ≤ x ≤ 0.74 from segmented targets

This study introduces novel triangle-like segmented targets for industrial-scale sputtering systems, which enable to distinctly reduce the workload in economic coating material development. Al, Cr and Cr/Al 50/50 target segments were assembled pairwise to synthesize Cr1−xAlxN hard coatings in the range of 0.21≤x≤0.74 at a high compositional resolution within two deposition runs. The obtained coating compositions are supported with TRIM simulations showing distinct differences in the sputtering characteristics of Al and Cr. X-ray diffraction reveals a solubility limit of x=0.61 in cubic Cr1−xAlxN. The evolution of structural and mechanical properties with composition is discussed in detail. The high potential and industrial relevance of the coatings with a maximum hardness of 25.2GPa is corroborated by excellent tribological properties with low friction values down to 0.4 and wear coefficients down to 1.8·10−16m3/Nm.

MoS2 sputtering coating for ultrahigh vacuum manipulation

Lubrication applied to sliding part is one of the key components for the development of high performance driving mechanism and manipulator in ultrahigh vacuum. Some solid lubrication has been widely used for this purpose, especially molybdenum disulfide (MoS2). Low friction, low wear and low outgassing during the sliding motion on lubrication are required for a high performance manipulation in ultrahigh vacuum. Although the tribology of MoS2 has been reported to be suitable in a vacuum, the outgassing characteristics while sliding are not clean, in this work, we investigate the characteristics of MoS2 sputtering coating in order to develop high performance ultrahigh vacuum driving mechanism. Their friction and outgassing characteristics were evaluated and we have found out suitable parameters for manipulation.

X 線光電子分光分析法および飛行時間型二次イオン質量分析法におけるアルゴンガスクラスターイオンビームの応用

The recent applications of argon gas cluster ion beam (GCIB) for X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) are briefly reviewed. Depth profiling of organic materials has been one of the most notable challenges in conventional XPS and TOF-SIMS. Recently, it is getting widely accepted that GCIB has enabled us to obtain the depth profiles of organic materials. GCIB has unique sputtering characteristics, such as extremely low chemical damage, high sputtering yield and surface smoothing capability. These superior characteristics facilitate diverse applications of XPS and TOF-SIMS, increasing the analysis of organic devices and advanced polymers. In this review, the recent applications of GCIB are discussed, focusing on the organic film depth profiling and the surface cleaning effect.

Characterization of carbon-supported platinum nano-particles synthesized using magnetron sputtering for application in PEM electrochemical systems

An innovative approach to the synthesis of nanostructured carbon-supported platinum electrocatalysts for application in proton-exchange membrane (PEM) electrochemical systems has been developed. Platinum nano-particles were deposited onto the carbon carrier using magnetron-ion sputtering. A special device has been developed to promote the effective stirring of the carbon carrier during catalyst deposition. Electrocatalytic powders thus obtained have been analyzed using XRD and TEM. The electrochemical performances of Pt/C based electrodes were studied in liquid electrolyte and in single-cell PEM fuel cell and water electrolyzer. Adjustment of sputtering process parameters (discharge power, sputtering time, bias voltage) led to the formation of electrocatalysts of high active surface area (up to 44 m2 g−1), high chemical purity and high electrochemical activity. A qualitative correlation between sputtering parameters and characteristics of electrocatalysts was established.