High Temperature Ion Implantation Research Articles

이온주입 제어에 의한 재료특성 개선에 관한 연구

In this study, techniques of ion implantation were used in order to improve the characteristics of metal materials such as the oxidation and wear resistant. In particular it is necessary to develope their oxidation and wear resistant that could be used in severe environmental conditions. There are mainly two elementary technologies including ion implantation and/or thin film coating. Ion implantation method was performed for surface modification. As a result, it was found that some ion implantations methods such as Nb, high-temperature Nb ion implantation and Nb+C combined implantation are somewhat effective for improving the oxidation resistance of TiAl alloy. Furthermore, the fluorine PBII treatment is more effective for improving the oxidation resistance of the TiAl alloy with three-dimensional shapes. The implantation of boron ion into thin film of TiN was also effective for improving the properties of materials like high temperature wear resistance. TiCrN film was applied to the actual seal ring for steam turbines, and it was observed that its sliding property showed a successfully good performance.

Local structure of Fe incorporated in GaInP layers by high temperature ion implantation

We have performed a structural investigation of the atomic environment of Fe impurities introduced by high temperature ion implantation in MOVPE grown GaInP layers. The lattice location of the implanted Fe atoms has been investigated by means of proton-induced X-ray emission in channeling geometry while X-ray absorption spectroscopy measurements have been performed to study the Fe local structure. The effect of post-implantation thermal treatments and the role of the substrate doping have been studied and discussed in comparison with the results obtained for Fe implantation in InP. An increased thermal stability of the substitutional Fe atoms in the GaInP lattice with respect to InP has been observed, whereas no effect related to the n-doping has been pointed out.

Multifunctional biocompatible nanostructured coatings for load-bearing implants

To take advantage of the self-propagating high-temperature synthesis (SHS) technique, magnetron sputtering (MS), and ion implantation assisted magnetron sputtering (IIAMS), a new type of biocompatible nanostructured film was developed and studied. Films of Ti–Ca–C–O–(N), Ti–Ca–P–C–O–(N), Ti–Si–Zr–O–(N), and Ti–Zr–C–O–(N) were deposited by DC MS or IIAMS of SHS composite targets TiC 0.5 + CaO, TiC 0.5 + CaO + TiO 2, TiC 0.5 + Ca 10(PO 4) 6(OH) 2, Ti 5Si 3 + ZrO 2, and TiC 0.5 + ZrO 2 in an Ar atmosphere or reactively in a gaseous mixture of Ar + 14% N 2. The films were characterized in terms of their structure, chemical, mechanical, and tribological properties. The biocompatibility of the films was evaluated by both in vitro and in vivo experiments. In vitro studies involved the investigation of adhesion, spreading and proliferation of Rat-1 fibroblasts, MC3T3-E1 osteoblasts, and IAR-2 epithelial cells, morphometric analysis, actin cytoskeleton and focal contacts staining of the cells cultivated on the films. Alkaline phosphatase activity and von Kossa staining of osteoblastic culture were investigated. Three groups of the in vivo investigations were fulfilled. Teflon plates coated with the tested films were inserted subcutaneous in mice and analysis of the population of cells on the surfaces was performed. Implantation studies of Ti rings and Ti rods coated with tested films using rat calvarian and hip defect models were also fulfilled. The results obtained show that Ti-based multicomponent films possess a combination of high hardness and adhesion strength, reduced Young's modulus, low wear and friction, high corrosion resistance with bioactivity, biocompatibility and non-toxicity that makes the films promising candidates as tribological coatings to be used for various medical applications like orthopedic prostheses, materials for connective surgery and dental implants.

High Dose High Temperature Ion Implantation of Ge into 4H-SiC

A box like Ge distribution was formed by ion implantation at 600°C. The Ge concentration was varied from 1 to 20 %. The TEM investigations revealed an increasing damage formation with increasing implantation dose. No polytype inclusions were observed in the implanted regions. A detailed analysis showed different types of lattice distortion identified as insertion stacking faults. The lattice site location analysis by “atomic location by channelling enhanced microanalysis” revealed that the implanted Ge is mainly located at interstitial positions.

Low-resistance p+ layer formation into diamond using heavily B ion implantation

We examine the B dosage dependence of the lattice and electronic structures of a heavily B doped layer formed by multiple-energy B-implantation into diamond (up to 1.7×1017Bcm−2) at an elevated temperature. The resultant highly B doped diamond layer exhibits p-type conduction with very low sheet resistance of 90Ω∕◻ (0.25μm thickness) and low resistivity of 2.3mΩ cm and has temperature-independent transport properties. This suggests that a high-temperature ion implantation technique allows the formation of diamond as a p-type degenerate semiconductor with metallic conduction and provides a useful tool for selective doping required for practical diamond device processing.

Ion beam analyses and electrical characterization of substitutional Fe properties in Fe implanted InP

We have investigated the structural and electrical behavior of Fe centers introduced in InP by high temperature ion implantation. The effect of post-implantation annealing treatments on the crystal damage and the lattice location of the Fe atoms was studied by PIXE-RBS-channeling measurements. Current–voltage measurements and simulations were used to characterize the electrical properties due to the presence of Fe-related deep traps. The results show that the background n-doping density plays a crucial role in controlling the annealing behavior and the electrical activation of the Fe centers.

Synthesis of room-temperature ferromagnetic Cr-doped TiO2(1 1 0) rutile single crystals using ion implantation

Ferromagnetic Cr-doped rutile TiO2 single crystals were synthesized by high-temperature ion implantation. The associated structural, compositional and magnetic properties were studied by X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, proton induced X-ray emission, X-ray diffraction, Cr K- and L-shell near-edge X-ray absorption spectroscopy and vibrating sample magnetometry. Cr was distributed uniformly to the depth of about 300nm with an average concentration of ∼1at.%. The samples are semiconducting and ferromagnetic as implanted, with a saturation magnetization of 0.29μB/Cr atom at room temperature. Cr is in a formal oxidation state of +3 throughout the implanted region and no CrO2 is detected.

Incorporation of active Fe impurities in GaInP by high temperature ion implantation

Single GaInP layers, grown by MOVPE lattice matched to GaAs, were implanted with Fe at T=200°C and annealed at 450 or 600°C. The role of implantation temperature and fluence in determining the crystal damage, and the damage recovery by annealing are investigated by RBS-channeling measurements. The redistribution of the Fe atoms is studied by means of SIMS depth profiling. The electrical properties related to Fe implantation are studied by current–voltage measurements. The results allow a first analysis of the similarities and the differences showed by the Fe implanted GaInP with respect to the InP case.

Synthesis of single-phase carbon nitride film prepared by hot implantation

High temperature ion implantation (hot implantation) is used to synthesize carbon nitride (CN x ) films. Three CN x films are compared by near edge X-ray absorption fine structure (NEXAFS) spectroscopy; one is prepared by room temperature implantation, another is prepared by subsequent annealing, and the other is prepared by hot implantation. The former two films show three comparable discrete peaks in N K-edge NEXAFS spectra, which are assigned to different kinds of local structures at N sites. On the other hand, a single peak grows predominantly in the spectra for the film prepared by hot implantation. Through the polarization dependence analysis of NEXAFS, the dominant peak is assigned to the fullerene-like structure of CN x which consists of pentagons and hexagons. The difference between the CN x films which are synthesized by subsequent annealing and hot implantation is also discussed.

Role of the Substrate Doping in the Activation of Fe2+ centers in Fe implanted InP

AbstractWe have investigated the structural and electrical behavior of Fe centers introduced in InP by high temperature ion implantation. The lattice location of the Fe atoms and the effect of postimplantation annealing treatments have been studied by PIXE-channeling measurements. I-V, CV and DLTS analyses have been used to characterize the electrical properties related to the presence Fe2+/3+ deep traps. The results show that the background n-doping density play a crucial role in controlling the annealing behavior and the electrical activation of the Fe centers. The same effect has been observed in samples containing Fe concentrations both above and below the Fe solubility threshold in InP.

B–C–N hybrid synthesis by high-temperature ion implantation

In order to synthesize B–C–N hybrid thin films, borazine (B 3N 3H 6) ion plasma was implanted in graphite at room temperature (RT) and 600 °C. The X-ray photoelectron spectroscopy (XPS) study suggested that B atoms in the deposited films are in a wide variety of atomic environment such as BC 3, BN 3 and B–C–N hybrid. The ratios of these coordinations strongly depend on the temperature during the ion implantation. It was found that the B–C–N hybrid is predominantly synthesized by the implantation at 600 °C where the surface [B]/([B] + [C] + [N]) ratio ranges from 0.1 to 0.35. The results imply that it is possible to control the composition of B–C–N hybrid by changing the fluence of the ion plasma and the temperature of graphite during ion implantation.

Research and development of oxidation, wear and corrosion resistant materials at high temperature by surface modification using ion processing

A multi-year project has been carried out to develop the oxidation, wear and corrosion resistant materials at high temperature for saving energy or reducing discharge of CO 2. The elementary technologies for surface modification include ion implantation and/or thin film coating. Furthermore, plasma-based ion implantation (PBII) techniques were investigated for developing ion implantation technique to the specimens with three-dimensional shapes. As a result, it was found that the ion implantation with some elements including Nb, high-temperature Nb ion implantation and Nb+C combined implantations are effective for improving the oxidation resistance of TiAl alloy. Also, fluorine PBII treatment is effective for improving the oxidation resistance of the TiAl alloy with three-dimensional shapes. Furthermore, the thin film coating of high-Al alloys such as CoNiCrAlY, TiAlN and NiCrAl provide a promising surface modification method for improving the oxidation, wear and corrosion resistance of steels and alloys at high temperature. These effects are based on formation of a protective Al 2O 3 oxide scale on material surfaces. For practical application to sliding seal materials, the TiCrN film was applied to the actual seal ring for steam turbines, and its sliding properties were successful performance. The techniques proposed in this project provide useful information for all of the material systems required to use at elevated temperature. Several results of practical applications will be presented along with laboratory test results.

Room-temperature ferromagnetism in ion-implanted Co-doped TiO2(110) rutile

Ferromagnetic Co-doped rutile TiO2 single crystals were synthesized by high-temperature ion implantation and characterized by a variety of techniques. Co is uniformly distributed to a depth of ∼300 nm with an average concentration of ∼2 at. %, except in the near-surface region, where the concentration is ∼3 at. %. Ferromagnetic behavior is exhibited at room temperature with an effective saturation magnetization of ∼0.6 μB/Co atom. The Co is in a formal oxidation state of +2 throughout the implanted region, and no Co(O) is detected.

Atomic environment of Fe following high-temperature implantation in InP

We report on the structural investigation of the atomic environment of Fe impurities introduced in InP by high-temperature ion implantation. The lattice location of the implanted Fe atoms and its evolution upon annealing treatments have been investigated by means of proton-induced x-ray emission and Rutherford backscattering spectrometry in channeling conditions. X-ray absorption spectroscopy measurements have been performed in order to study the Fe local structure. The results of these measurements have been correlated to those obtained with other structural characterization techniques, as transmission electron microscopy and high-resolution x-ray diffraction, and provide an overall picture of the Fe incorporation mechanisms at the atomic level. It has been found that the high-temperature implantation process favors the incorporation of Fe in high-symmetry sites. Conversely, the point defect flux occurring during high-temperature annealing controls the kick-out of the Fe atoms from substitutional locations, leading to the formation of Fe-P complexes.

GaN evaporation and enhanced diffusion of Ar during high-temperature ion implantation

GaN films were implanted with 150 keV Ar+ at temperatures up to 1100 °C to a dose of 3×1015 cm−2. Concentration profiles of Ar were measured by secondary ion mass spectroscopy and depth distributions of ion-induced damage were estimated from Rutherford backscattering/channeling spectra. No redistribution of Ar atoms was detected up to 700 °C. At 1000 °C a deep penetrating diffusion tail and a shift of the Ar peak to the surface were observed. At temperatures higher than 800 °C shift of the damage peak to the surface was also observed. We attributed the shift of the Ar peak and the damage peaks to evaporation of thin layer of GaN during high-temperature implantation and estimated its temperature dependence.

GaN evaporation and enhanced diffusion of Ar during high-temperature ion implantation

GaN evaporation and enhanced diffusion of Ar during high-temperature ion implantation

Masking Process for High-Energy and High-Temperature Ion Implantation

Masking Process for High-Energy and High-Temperature Ion Implantation

Incorporation of Highly Concentrated Iron Impurities in InP by High Temperature Ion Implantation

AbstractIron was introduced in InP by ion implantation with the aim of obtaining a high concentration of substitutional, electrically active, deep level impurities. A substrate temperature higher than 200 °C was maintained during implantation in order to reduce damage accumulation and Fe defect reactions. The lattice position of the implanted Fe atoms and its modification during annealing treatments was studied by means of Proton Induced X-ray Emission (PIXE) in channeling conditions and correlated with the ion induced damage measured by different techniques. The results show that a high fraction of substitutional Fe atoms is present after the implantation. This fraction is progressively reduced during thermal treatments by increasing the annealing temperature, with the formation of inactive Fe aggregates, probably in the form of small Fe-P complexes.

Cesium Ion Implantation in Single Crystal Yttria-Stabilized Zirconia (YSZ) and Polycrystalline MgAl2O4-YSZ

ABSTRACTYSZ and MgAl2O4-YSZ composite are two promising materials as in the inert matrix nuclear fuel for the incineration of plutonium. In this study, 400 keV Cs ions were implanted to a fluence of 1×1017 ions/m2 in both materials in order to investigate the retention behavior of fission product at elevated temperature. The implantations were completed at room temperature for the YSZ and 973 K for MgAl2O4-YSZ, respectively. Subsequent annealing at 1273 K was performed after a room temperature implantation of YSZ. After annealing, a high density of gas bubbles formed with diameter from 3 to 40 nm from the surface to a depth of 150 nm in the YSZ matrix. The swelling due to bubbles formation was estimated to be 2.5%. In situ TEM was employed during high temperature ion implantation of the MgAl2O4-YSZ composite. A high density of small bubbles with 5 nm in diameter formed in the MgAl2O4 and YSZ grains after an ion dose of 1×1017 ions/cm2. There was no preferential precipitation along grain boundaries. Electron Paramagnetic resonance (EPR) spectroscopy was used to investigate the type of defects that formed in the YSZ matrix.

Development of a continuously variable energy radio frequency quadrupole accelerator for SiC power semiconductor device fabrication

High energy ion implantation is an important process for controlling deep junction conductivity of SiC semiconductor devices. An radio frequency quadraupole (RFQ) accelerator can accelerate high current ions, but the conventional RFQ accelerator is unable to accelerate various ions with different energies. In order to form the box profile with a low number of defects, a high current MeV ion implanter was constructed using a newly designed continuously variable energy RFQ accelerator and high temperature ion implantation chamber. Results of the experiment showed that the resonance frequency varied from 11.7 to 29.3 MHz, so the output beam energy could be changed over a range of about 6.3 times. The results also showed a higher Q-value of over 5000 compared with that of a conventional machine of 1500. Beam acceleration tests were performed using Al ions, and beams were accelerated from 20 to 750 keV using an radio frequency power of 15 kW. The ions were implanted into 4H-SiC, and the projected ranged was 0.76 μm measured by secondary ion mass spectroscopy.