Etch characteristics of HfO2 thin films by using CF4/Ar inductively coupled plasma

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity) of HfO₂ thin films in the CF₄/Ar inductively coupled plasma (ICP). The maximum etch rate of 54.48 nm/min for HfO₂ thin films was obtained at CF₄/Ar (=20:80%) gas mixing ratio. At the same time, the etch rate was measured as function of the etching parameters such as ICP RF power, DC-bias voltage, and process pressure. The X-ray photoelectron spectroscopy analysis showed an efficient destruction of the oxide bonds by the ion bombardment as well as an accumulation of low volatile reaction products on the etched surface. Based on these data, the chemical reaction was proposed as the main etch mechanism for the CF₄-containing plasmas.     

Etch characteristics of FePt magnetic thin films using inductively coupled plasma reactive ion etching

Etch characteristics of L10 FePt thin films masked with TiN films were investigated using an inductively coupled plasma (ICP) reactive ion etching in a CH₃OH/Ar plasma. As the CH₃OH gas was added to Ar, the etch rates of FePt thin films and TiN hard mask gradually decreased, and the etch profile of FePt films improved with high degree of anisotropy. With increasing ICP rf power and dc-bias voltage to substrate and decreasing gas pressure, the etch rate increased and the etch profile becomes vertical without any redepositions or etch residues. Based on the etch characteristics and surface analysis of the films by X-ray photoelectron spectroscopy, it can be concluded that the etch mechanism of FePt thin films in a CH₃OH/Ar gas does not follow the reactive ion etch mechanism but the chemically assisted sputter etching mechanism, due to the chemical reaction of FePt film with CH₃OH gas.     

Etch damage characteristics of TiO2 thin films by capacitively coupled RF Ar plasmas

Etch damage of TiO₂ thin films with the anatase phase by capacitively coupled RF Ar plasmas has been investigated. The plasma etching causes a mixed phase of anatase and rutile or the rutile phase. The effect of Ar plasma etching damage on degenerating TiO₂ thin films is dependent on gas pressure and etching time. The physical etching effect at a low gas pressure (1.3 Pa) contributes to the degradation: the atomic O concentration at the thin film surface is strongly increased. At a high gas pressure (13-27 Pa) and long etching time (60 min), there are a variety of surface defects or pits, which seem to be similar to those for GaN resulting from synergy effect between particle and UV radiation from the plasmas. For the hydrophilicity, the thin film etched at the high gas pressure and a short etching time (5 min) seems to have no etch damage: its contact angle property is almost similar to that for the as-grown thin film, and is independent of the black light irradiation. This result would probably result from formation of donor-like surface defects such as oxygen vacancy.     

SERS-active silver nanoparticle aggregates produced in high-iron float glass by ion exchange process

Silver nanoparticles were produced in iron containing float glasses by silver-sodium ion exchange and post-annealing. In particular, the effect of the concentration and the oxidation state of iron in the host glass on the nanoparticle formation was studied. After the nanoparticle fabrication process, the samples were characterized by optical absorption measurements. The samples were etched to expose nanoparticle aggregates on the surface, which were studied by optical microscopy and scanning electron microscopy. The SERS-activity of these glass samples was demonstrated and compared using a dye molecule Rhodamine 6G (R6G) as an analyte. The importance of the iron oxidation level for reduction process is discussed. The glass with high concentration of Fe²⁺ ions was found to be superior in SERS applications of silver nanoparticles. The optimal surface features in terms of SERS enhancement are also discussed.     

Etch characteristics of TiN/Al2O3 thin film by using a Cl2/Ar adaptive coupled plasma

In this study, we carried out an investigation in the etching characteristics of TiN thin films in a C1₂/Ar adaptive coupled plasma. The maximum etch rate of the TiN thin films was 768 nm/min at a gas mixing ratio of C1₂ (75%)/Ar (25%). At the same time, the etch rate was measured as functions of the various etching parameters. The X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment as well as the accumulation of low volatile reaction products on the etched surface. Field emission Auger electron spectroscopy analysis was used to examine the efficiency of the ion-stimulated desorption of the reaction products.     

p-type doping of ZnO by means of high-density inductively coupled plasmas

A custom-designed inductively coupled plasma assisted radio-frequency magnetron sputtering deposition system has been used to fabricate N-doped p-type ZnO (ZnO:N) thin films on glass substrates from a sintered ZnO target in a reactive Ar + N₂ gas mixture. X-ray diffraction and scanning electron microscopy analyses show that the ZnO:N films feature a hexagonal crystal structure with a preferential (002) crystallographic orientation and grow as vertical columnar structures. Hall effect and X-ray photoelectron spectroscopy analyses show that N-doped ZnO thin films are p-type with a hole concentration of 3.32 × 10¹⁸ cm^− 3 and mobility of 1.31 cm² V^− 1 s^− 1. The current-voltage measurement of the two-layer structured ZnO p-n homojunction clearly reveals the rectifying ability of the p-n junction. The achievement of p-type ZnO:N thin films is attributed to the high dissociation ability of the high-density inductively coupled plasma source and effective plasma-surface interactions during the growth process.     

Etch characteristics of IrMn thin films using an inductively coupled plasma of CH3OH/Ar

An inductively coupled plasma reactive ion etching of IrMn magnetic thin films patterned with Ti hard mask was studied in a CH₃OH/Ar gas mix. As the CH₃OH concentration increased, the etch rates of IrMn thin films and Ti hard mask decreased, while the etch profiles improved with high degree of anisotropy. The effects of coil rf power, dc-bias voltage to substrate and gas pressure on the etch characteristics were investigated. The etch rate increased and the etch profile improved with increasing coil rf power, dc-bias voltage and decreasing gas pressure. X-ray photoelectron spectroscopy revealed that the chemical reaction between IrMn films and CH₃OH gas occurred, leading to the clean and good etch profile with high degree of anisotropy of 90°.     

Dry etching of magnesium oxide thin films by using inductively coupled plasma for buffer layer of MFIS structure

Magnesium oxide thin film has been widely used as a buffer layer and substrate for growing various thin film materials because of very low Gibbs free energy, low dielectric constant and low refractive index. The investigations of the MgO etching characteristics in BCl₃/Ar plasma were carried out using the inductively coupled plasma system. It was found that the increasing BCl₃ in the mixing ratio of BCl₃/Ar plasma causes monotonic MgO etch rate. The results showed in the BCl₃-rich plasma that the etching process is dominantly supplied by the chemical pathway through the ion-assisted chemical reaction.     

Surface modification of medical metals by ion implantation of silver and copper

Implant related infections remain a concern in modern surgery. Surface modification is an effective way to reduce the occurrence of these complications. Of various techniques, ion implantation shows promise. In the present work, silver and copper were ion implanted separately, into three typical medical metals, namely 317L stainless steel, titanium, and Ti-Al-Nb by a MEVVA ion source machine at various ion doses. The objective of this study was to determine the influence of silver and copper ion implantation on antibacterial performance and wear and corrosion resistance of the three materials. Antibacterial activity of silver- and copper-implanted samples against Staphylococcus aureus were assessed by the plate-counting method. The results show that silver and copper implantation improves the antibacterial rate and wear performance of all the three metals studied. It is also found that silver ion implantation does not change the corrosion resistance while the corrosion resistance of copper-implanted samples shows a significant decline. In conclusion, silver ion implantation is favorable to copper ion implantation for increasing the antibacterial nature of these three metals.     

Thermal activation energy of silver in ion-exchanged soda–lime glass investigated by X-ray photoelectron spectroscopy

The thermal effect on silver in ion-exchanged glasses was investigated in situ by X-ray photoelectron spectroscopy (XPS) in an ultra-high vacuum environment. Each XPS signal of Ag 3d_3/2 and 3d_5/2 consists of two components, the metallic state (Ag⁰) and the oxidized state (Ag⁺), resolved after curve fitting. The toward-surface diffusion of silver was observed by monitoring the changes in concentration on the surface during sample annealing between 20 and 450°C. Judging from the variations in line shape and binding energy and from the enhancement of surface silver under annealing, both metallic and oxidized silver are accumulated on the surface. By applying the diffusion theory in a semi-infinite system to the experimental data, the thermal activation energy of the oxidized silver in ion-exchanged glass, 0.16 eV, was estimated. The activation energy of metallic Ag precipitated during heating, 0.23 eV, was estimated as well.     

电感耦合等离子体发射光谱法测定矿石中银的研究

目前,实验室测定矿石中银的方法主要有银的光度法、火焰原子吸收光谱法、石墨炉原子吸收光谱法等等,为了更好的简化测量过程、提高工作效率,本文旨在建立更适宜的、能满足于高中低含量银的测试方法,采用电感耦合等离子体光谱法测定金属矿中银的含量.样品采用氢氟酸、硝酸、硫酸(体积比10∶5∶1)溶解,赶净氟和破坏有机物后,经(1+1...     

Etch characteristics of indium zinc oxide thin films using inductively coupled plasma of a Cl2/Ar gas

Inductively coupled plasma reactive ion etching of indium zinc oxide (IZO) thin films masked with a photoresist was performed using a Cl₂/Ar gas. The etch rate of the IZO thin films increased as Cl₂ gas was added to Ar gas, reaching a maximum at 60% Cl₂ and decreasing thereafter. The degree of anisotropy in the etch profile improved with increasing coil rf power and dc-bias voltage. Changes in pressure had little effect on the etch profile. X-ray photoelectron spectroscopy confirmed the formation of InCl₃ and ZnCl₂ on the etched surface. The surface morphology of the films etched at high Cl₂ concentrations was smoother than that of the films etched at low Cl₂ concentrations. These results suggest that the dry etching of IZO thin films in a Cl₂/Ar gas occurs according to a reactive ion etching mechanism involving ion sputtering and a surface reaction.     

Optimized inductively coupled plasma etching for poly(methyl-methacrylate-glycidly-methacrylate) optical waveguide

Optical loss is a crucial quality for the application of polymer waveguide devices. The optimized oxygen inductively coupled plasma etching conditions, including antenna power, bias power, chamber pressure, O₂ flow rate and etching time for the fabrication of smooth vertical poly(methyl-methacrylate-glycidly-methacrylate) channel waveguide were systematically investigated. Atomic force microscopy and scanning electron microscopy were used to characterize the etch rate, surface roughness and vertical profiles. The increment of etch rate with the antenna power, bias power and O₂ flow rate was observed. Bias power and chamber pressure were found to be the main factor affecting the interface roughness. The vertical profiles were proved to be closely related to antenna power, bias power and O₂ flow rate. Surface roughness increment was observed when the etching time increased.     

Polyelectrolyte multilayer films containing silver as antibacterial coatings

A facile approach to fabrication of transparent antimicrobial coatings based on polyelectrolyte multilayers (PEMs) is presented. Counterions existing in PEMs were utilized via ion exchange and in situ reduction to incorporate into the films silver ions and nanoparticles, and the antibacterial efficacy of the films against E. coli was assessed by the Kirby-Bauer method. The PEMs containing silver in the ionic form exhibited high activities in short terms, and the antibacterial effects depended on the ionic strength in the polyelectrolyte solutions used for the PEM fabrication. The PEMs loaded with silver nanoparticles showed lower initial bactericidal effects, but remained active after long periods of time, and the antimicrobial performance can be improved by increasing the silver loading through repeating the ion-exchange/reduction cycle for multiple times. The films were transparent in the visible region. Coatings containing multiple antimicrobial agents for possible synergistic effects can be fabricated in a single process using this method.     

Ion energy distribution of an inductively coupled radiofrequency discharge in argon and oxygen

We report an experimental investigation of the ion energy distribution in an inductively coupled electron cyclotron wave resonance (ECWR) discharge with a superimposed static magnetic field. The inductively coupled discharge is sustained by applying a 13.56 MHz radiofrequency (RF) power to an aluminium single-turn coil located inside the vacuum chamber. The source region was separated by a grid from the diffusion region. Ion energy distribution (IEDF) measurements employing an energy-dispersive mass spectrometer or plasma process monitor (PPM) whose entrance opening was 15 cm away from the grid were performed in the diffusion region. The IEDF is composed of two peaks; a low-energy peak due thermalized ions and a high-energy peak due to ions coming directly from the source region without undergoing thermalization. The energetic difference between the groups thus reflects the plasma potential difference between the source region and the diffusion region. The pronounced intensity variation of the high-energy peak with increasing pressure is caused by charge-changing collisions yielding a depletion of the high-energy ions with increasing effective path length.     

离子束增强沉积TiN薄膜的研究

利用多功能离子束增强沉积设备，采用三种不同工艺方法制备TiN薄膜，并对制备的TiN薄膜进行了AES，XPS，XRD，RBS和TEM等分析。结果表明：所制备的薄膜都有很好均匀性，TiN薄膜处在压应力状态；在溅射沉积的同时，在0～20keV范围内，N 和Ar 离子的轰击使得TiN薄膜的生长呈现不同择优取向；随着N 离子轰击能量的增加，制备的TiN薄膜的晶粒增大。     

Comparison of the properties of BN films synthesized by inductively coupled r.f. and microwave plasmas

Thin films of boron nitride are synthesized by two plasma-enhanced chemical vapour deposition techniques: inductively coupled r.f. plasma (13.56 MHz) and microwave plasma (2.45 GHz). We study the composition (impurity level, B/N ratio), the proportion of c-BN phase in the films and other properties of those films as a function of various process parameters. Two boron and two nitrogen precursors are compared: trimethyl borazine and diborane, dini trogen and ammonia, respectively. The advantages and disadvantages of each combinations are presented. The deposition process is followed by optical emission spectroscopy. Adhesion is one of the main problems encountered for films containing c-BN.     

离子源辅助电子束沉积凹印版耐磨层

针时凹印版电镀存在的污染和高能耗，采用射频感应偶合（ICP）离子源辅助电子束沉积硬质铬耐磨层，通过控制离子源参数和加入过渡层来提高薄膜与基体的结合力和显微硬度。利用扫描电镜、原子力显微镜、显微硬度计、划痕仪、表面轮廓仪，摩擦磨损仪对膜层的组织结构和性能进行了研究，探讨了在薄膜沉积过程中，离子源工艺参数对薄膜界面结合机理，组织结构和性能的影响。     

Dry etching of TaN thin film using CH4/Ar inductively coupled plasma

In this research, we investigated the TaN etch rate and selectivity with under layer (HfO₂) and mask material (SiO₂) in inductively coupled CH₄/Ar plasma. As the CH₄ content increased from 0% to 80% in CH₄/Ar plasma, the TaN etch rate was increased from 11.9 to 22.8 nm/min. From optical emission spectroscopy (OES), the intensities for CH [431 nm] and H [434 nm] were increased with the increasing CH₄ content from 0% to 100% in CH₄/Ar plasma. The results of x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) showed no accumulation of etch by-products from the etched surface of TaN thin film. As a result of OES, AES and XPS analysis, we observed the etch by-products from the surfaces, such as Ta-N-CH and N-CH bonds. Based on the experimental results, the TaN etch was dominated by the chemical etching with the assistance of Ar sputtering in reactive ion etching mechanism.