Carbon Implantation Research Articles

Laser ion source for semiconductor applications

Carbon implantation can be effectively used for axial minority charge carriers’ lifetime control in various silicon bulk and epitaxial planar structures. When carbon is implanted, more stable recombination centres are formed and silicon is not doped with additional impurities, as for example, when irradiated with protons or helium ions. Economically, such a process competes with alternative methods, and is more efficient for obtaining small lifetimes (several nanoseconds). I-3 ion injector with laser-plasma ion source at Institute for theoretical and experimental physics (ITEP) is used as ion implanter in semiconductors. The ion source uses pulsed CO2 laser setup with radiation-flux density of 1011 W/cm2 at target surface. The ion source produces beams of various ions from solid targets. The generated ion beam is accelerated in the two gap RF resonator at voltage of up to 2 MV per gap. Resulting beam energy is up to 4 MV per charge. Parameters of carbon ion beam generated and used for semiconductor samples irradiation during experiments for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures are presented.

Conductive Tracks in Carbon Implanted Titania Nanotubes: Atomic‐Scale Insights from Experimentally Based Ab Initio Molecular Dynamics Modeling

AbstractIon implantation of titania nanotubes is a highly versatile approach for tailoring structural and electrical properties. While recently self‐organized nanoscale compositional patterning has been reported, the atomistic foundations and impact on electronic structure are not established at this point. To study these aspects, ab initio molecular dynamic simulations based on atomic compositions in C implanted titania nanotubes according to elastic recoil detection analysis are employed. Consistent with experimental data, carbon accumulates in chainlike precipitates, which are favorable for enhancing conductivity, as revealed by density‐functional theory electronic ground states calculations are demonstrated.

Effects of carbon implantation on the low temperature magnetism behavior in amorphous Fe93Zr7 films

We present a detailed investigation on the effects of C-implantation on low temperature magnetic behavior in Fe93Zr7 amorphous films using spin wave theory, law of approach to saturation, and Alben and Becker's theory. Significant increase in Curie temperature with a decrease in coercivity were observed upon C-implantation. Bloch's law was used to analyze the temperature dependence of magnetization, and several important parameters were extracted such as the stiffness constant of the spin wave, and the exchange constant. The local random anisotropy constant decreases from 0.35 to 0.19 MJ/m3 with increasing carbon concentration from 0 to 11%. The ferromagnetic correlation length for which the anisotropy directions are assumed to be arbitrarily oriented increases significantly with increasing carbon content. By the use of the theory of Alben and Becker, we also extracted the local anisotropy from coercivity, and reasonable agreement was found with random magnetic anisotropy approach.

Вивчення ступеня інтеграції м’яких тканин в елементи з вуглець-вуглецевого композитного матеріалу в зоні переходу внутрішнього та зовнішнього середовища при імплантації ендо-екзопротезів

Щороку в Україні виконується близько 600 ампутацій на рівні стегна, що вимагає подальшої реабілітації у вигляді протезування втраченої кінцівки. Стандартним методом кріплення протеза до кукси стегна є фіксація гільзи протеза навколо кукси. Гільза забезпечує передачу навантаження, стабільність і ефективний контроль над протезом. Однак цей метод фіксації часто згадується як незадовільний через низку ускладнень, таких як виразки і подразнення шкіри, пітливість у гільзі, неможливість ходити по пересіченій місцевості, неналежний контроль над протезом, зниження діапазону рухів стегна і болі в ділянці кукси. Альтернативним рішенням є перкутанне кріплення протеза ноги до стегнової кістки за допомогою остеоінтегрованих імплантатів. Використовувалися інтрамедулярні стрижні з титановим покриттям, поєднані із зовнішнім блоком за допомогою замка, накритого силіконовою прокладкою, що виконує функцію розмежування внутрішнього середовища від зовнішнього, що часто призводило до інфекційно-запальних ускладнень. Пошук матеріалів для вирішення цих проблем зупинився на вуглецевих матеріалах, у тому числі вуглець-вуглецевих композитних матеріалах (ВВКМ), які є відносно новими конструкційними матеріалами в практиці ортопедії. Їх успішно використовують при остеосинтезі та ендопротезуванні кісток завдяки комплексу необхідних фізико-механічних і хімічних властивостей. Метою даної роботи було встановити ступінь інтеграції м’яких тканин і, зокрема шкірного покриву, в ВВКМ. Експериментальним шляхом, із використанням лабораторних тварин, проведено гістоморфологічний аналіз змін тканин в ділянці контакту з імплантатами. Доведено біоінертність матеріалу, а також обґрунтовано перспективність застосування імплантатів із ВВКМ як покриття елементів конструкцій ендо-екзопротезів для застосування в реконструктивній травматології та ортопедії.

Improvement of Fermi-Level Pinning and Contact Resistivity in Ti/Ge Contact Using Carbon Implantation.

Effects of carbon implantation (C-imp) on the contact characteristics of Ti/Ge contact were investigated. The C-imp into Ti/Ge system was developed to reduce severe Fermi-level pinning (FLP) and to improve the thermal stability of Ti/Ge contact. The current density (J)-voltage (V) characteristics showed that the rectifying behavior of Ti/Ge contact into an Ohmic-like behavior with C-imp. The lowering of Schottky barrier height (SBH) indicated that the C-imp could mitigate FLP. In addition, it allows a lower specific contact resistivity (ρc) at the rapid thermal annealing (RTA) temperatures in a range of 450–600 °C. A secondary ion mass spectrometry (SIMS) showed that C-imp facilitates the dopant segregation at the interface. In addition, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) mapping showed that after RTA at 600 °C, C-imp enhances the diffusion of Ge atoms into Ti layer at the interface of Ti/Ge. Thus, carbon implantation into Ge substrate can effectively reduce FLP and improve contact characteristics.

Finite element evaluation to compare stress pattern in bone surrounding implant with carbon fiber-reinforced poly-ether-ether-ketone and commercially pure titanium implants.

Background:Titanium allergy is a main reason for failure of dental implant. Hence, newer implant biomaterials have emerged such as zirconia and carbon or glass fiber reinforced poly-ether-ether-ketone (CFR-PEEK)-based materials. The aim of the present study was to compare the stress pattern in bone surrounding implant with CFR-PEEK and commercially pure titanium implant.Materials and Methods:Three-dimensional formal model of mandibular first molar partsubstituting with implant supported crown was generated. Implant with dimensions of 10 mm length and 4.3 mm diameter was used in this study. Finite element models of CFR-PEEK and commercially pure titanium implant assemblies were generated. A 100 Newton (N) force was implemented along the long axis and obliquely at 30° to the long axis of implant. Von Mises pressures generated in the bone surrounding implant were analyzed using ANSYS workbench 16.0 and other finite element software.Results:Similar stress distribution was detected in bone surrounding implant with CFR-PEEK implant and commercially pure titanium implant assembly under 100 N force applied vertically and obliquely.Conclusion:PEEK reinforced with carbon or glass fiber implants can be a viable alternative in individuals who are more of esthetic concern and who demonstrate allergy to metallic implants.

Increasing the photoluminescence intensity of silicon nitride by forming K and N radioactive centres

Creating a light emitter to transfer an electrical signal by optical way has a great importance in development of optoelectronics. The silicon nitride films studied by photoluminescence techniques, and determined luminescence is associated with presence of an extended zone of tail states. Defects play the main role in radiative recombination for structures annealed at 600 °C and 1100 °C. Photoluminescence (Pl) intensity of obtained films by plasma enhanced chemical vapor deposition is increased after annealing at 600 °C which are related to increased concentration of defects as a result of broken Si–H and N–H bonds. Due to the formation of N-centers through the breaking of N–H bonds, annealing at 1100 °C led to sharp decrease in the luminescence intensity 5 and 3 times for SiN1.1 and SiN1.5 samples respectively. Replacement of Si-Si bonds by Si-N enhance Eg with increasing stoichiometric parameter, which leads to blue shift edge of photoluminescence maximum. Carbon implantation of silicon nitride films with extra Si obtained by Plasma Enhanced Chemical Vapor deposition at 1x1014 cm‒2, 2x1015 cm‒2, and 1x1016 cm‒2 fluencies, in combination with prolonged annealing at 1100 °C temperature leads to the formation of additional K-centers.

Reduction of Fluorine Diffusion and Improvement of Dark Current Using Carbon Implantation in CMOS Image Sensor

Recently, the demand of a high resolution complementary metal-oxide semiconductor (CMOS) image sensor is dramatically increasing. As the pixel size reduces to submicron, however, the quality of the sensor image decreases. In particular, the dark current can act as a large noise source resulting in reduction of the quality of the sensor image. Fluorine ion implantation was commonly used to improve the dark current by reducing the trap state density. However, the implanted fluorine diffused to the outside of the silicon surface and disappeared after annealing process. In this paper, we analyzed the effects of carbon implantation on the fluorine diffusion and the dark current characteristics of the CMOS image sensor. As the carbon was implanted with dose of 5.0 × 1014 and 1 × 1015 ions/cm2 in N+ area of FD region, the retained dose of fluorine was improved by more than 131% and 242%, respectively than no carbon implantation indicating that the higher concentration of the carbon implantation, the higher the retained dose of fluorine after annealing. As the retained fluorine concentration increased, the minority carriers of electrons or holes decreased by more Si-F bond formation, resulting in increasing the sheet resistance. When carbon was implanted with 1.0 × 1015 ions/cm2, the defective pixel, dark current, transient noise, and flicker were much improved by 25%, 9.4%, 1%, and 28%, respectively compared to no carbon implantation. Therefore, the diffusion of fluorine after annealing could be improved by the carbon implantation leading to improvement of the dark current characteristics.

Pyrocarbon Implant for Trapeziometacarpal Arthritis: Mid-term Clinical and Radiological Results

AbstractPyrolytic carbon implants for trapeziometacarpal (TMC) arthritis have been extensively studied, but there is still discrepancy in the literature concerning the mid-term functional results. Our group describes the clinical and radiological results after five years of surgical management of TMC arthritis with Pyrodisk (Integra Life Sciences, Plainsboro, NJ, US). A total of 19 patients (2 males and 17 females) aged 56.45 ± 5.95 (range: 44 to 67) years were reviewed with a mean follow-up of 74.05 ± 14.43 (range: 60.00 to 105.83) months. At the final follow-up, the score on the Visual Analogue Scale (VAS) for pain was of 1.76 ± 2.05, the average score on the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire was of 22.73 ± 22.33, and all functional parameters were above the 90% barrier of the contralateral side. The progression of radiolucency was 89% at 1 year and 11% at 5 years of follow-up respectively, but it was not related to the clinical outcomes. The prevalence of subluxation (around one-fourth of the center of the implant) was of 24% in asymptomatic patients, and dislocation was not observed. The overall survival of the implant was of 89%. Revision took place in 11% of the cases due to persistent pain and implant breakage after direct impact. More than 75% of the patients were very or highly satisfied with the treatment. In conclusion, Pyrodisk enabled us to obtain good functional mid-term results, with an acceptable survival of the implant and low risk of dislocation. Radiological findings do not necessarily translate into clinical symptoms.

Influence of dual Ge/C pre-amorphization implantation on the Ni1−xPtxSi phase nucleation and growth mechanisms

The impact of dual Ge/C pre-amorphization implantation (PAI) processes on the Ni0.9Pt0.1(7 nm)/Si system phase sequence has been investigated by advanced X-ray diffraction techniques and transmission electron microscopy (TEM). Using a high carbon implantation dose, it is found that the expected development of Ni-rich phases is not observed: a thick amorphous Ni1−xPtxSi layer developed until Ni0.9Pt0.1 full consumption, followed by the development of a thin crystalline Ni1−xPtxSi layer along the TiN interface. By increasing the temperature further, this last one abruptly thicken, creating the final silicide layer. An alternative model to grain boundary diffusion is discussed, accounting for the final distribution of the foreign species within the silicide layer. The use of Ge in dual Ge/C PAI processes is proposed to impact the growing mechanisms by alloying to fine-tune the carbon distribution in the substrate sub-surface.

Optically transparent electrodes to study living cells: A mini review.

The use of electrochemical methods to study living systems, including cells, has been of interest to researchers for a long time. Thus, controlling the polarization of the electrode contacting living cells, one can influence, for example, their proliferation or the synthesis of specific proteins. Moreover, the electrochemical approach formed the basis of the biocompatibility improvement of the materials contacting with body tissues that use in carbon hemosorbents and implants development. It became possible to reach a fundamentally new level in the study of cell activity with the introduction of optically transparent electrodes in this area. The advantage of the using of optically transparent electrodes is the possibility of simultaneous analysis of living cells by electrochemical and microscopic methods. The use of such materials allowed approaching to the study of the influence of the electrode potential on adhesion activity and morphology of the different cell types (HeLa cells, endothelial cell, etc.) more detailed. There are a negligible number of publications in this area despite the advantages of the usage of optically transparent electrodes to study living cells. This mini-review is devoted to some aspects of the interaction of living cells with conductive materials and current advances in the use of optically transparent electrodes for the study of living cells, as well as the prospects for their use in cellular technologies.

Broad Diversity of Near-Infrared Single-Photon Emitters in Silicon.

We report the detection of individual emitters in silicon belonging to seven different families of optically active point defects. These fluorescent centers are created by carbon implantation of a commercial silicon-on-insulator wafer usually employed for integrated photonics. Single photon emission is demonstrated over the 1.1-1.55 μm range, spanning the O and C telecom bands. We analyze their photoluminescence spectra, dipolar emissions, and optical relaxation dynamics at 10K. For a specific family, we show a constant emission intensity at saturation from 10K to temperatures well above the 77K liquid nitrogen temperature. Given the advanced control over nanofabrication and integration in silicon, these individual artificial atoms are promising systems to investigate for Si-based quantum technologies.

Regularities of PLA mechanical property modification under ion implantation conditions

The investigations of the surface physicochemical properties of polylactic acid (PLA) modified by argon, carbon and silver ion implantation to fluences of 1∙1014, 1∙1015 and 1∙1016 cm−2 and energies of 20 keV, 20 keV and 42 keV respectively are described. The projected ion ranges in the polymer matrix are estimated by the computer simulation with the TRIDYN code, as well as energies of electron and nuclear stopping are assessed according to the SRIM modelling. The microhardness and elastic modulus are established to be dependent on the degree of crystallinity of the material. It was found that the microdistortions and strains of the PLA crystal lattice increase after ion implantation due to the structural alteration and defect formation. Long-range effect expressed as bigger depth of modified surface layer than the ion range in the material is suggested as a result of the radiation-stimulated diffusion and thermal restructuring of the material.

Structural and Photoluminescence Analysis on the Implantation of Carbon and Proton for the Creation of Damage-Assisted Emission in Silicon

We study the induced defects in the depth profiling of the silicon structure after being implanted with carbon and followed by high energy proton irradiation. It has been reported before that the formation of the optically active point-defect, specifically the G-centre is due to the implantation and irradiation of carbon and proton, respectively. It is crucial to quantify the diffusional broadening of the implanted ion profile especially for proton irradiation process so that the radiation damage evolution can be maximized at the point-defect formation region. Profiling analysis was carried out using computational Stopping and Range of Ions in Matter (SRIM) and Surrey University Sputter Profile Resolution from Energy Deposition (SUSPRE) simulation. The energies of carbon ions adopted for this investigation are 10, 20, 30, and 50 keV, while proton irradiation energy was kept at 2 MeV. Photoluminescence measurements on silicon implanted with carbon at different energies were carried out to study the interrelation between the numbers of vacancies produced during the damage event and the peak emission intensities.

A review on surface treatment of titanium implant

Dental implants are fixtures that serve as replacements for the root of the missing natural tooth and in the current day dental practice. Success or failure of the dental implant treatment is mainly based on the principles of osseointegration, which is the direct and stable anchorage of an implant due to the formation of bony tissue around the implant. A number of systemic and local factors influence the production of an osseointegrated interface and therefore the stability of the implant. Present article covers various methods used for surface treatment of titanium and titanium alloy implants. They are mechanical method such asMachining,Grinding,Polishing and Grit blasting. Chemical treatment include Acid treatment,Hydrogen peroxide treatment,Alkali treatment.Sol–gel coatings include TiO2 coating,Calcium phosphate coatings, Titania/hydroxyapatite composite coatings and Silica coating.Electrochemical treatments includes Thermal spraying,Plasma spraying.Ion implantation and deposition include Oxygen implantation, Nitrogen implantation,Carbon implantation and deposition, Metal ion implantation. Surface modification methods used to improve the mechanical, chemical and biological properties of titanium and its alloys for biomedical application. Keywords: Surface treatment, Osseointegration, Biomaterials, Microtopography, Biocompatibility.

Direct Graphene Synthesis on Lithium Niobate Substrate by Carbon Ion Implantation

A dozen-micron-scale 4-7 layers of graphene was synthesized directly on Lithium Niobate (LiNbO3, LN) by carbon implantation in nickel covered LiNbO3 film. The 1.52E16 ions·cm-2 carbon ions of 80KeV were implanted to the nickel film with the implantation depth of 100nm, which is close to the interface between the nickel film and LiNbO3. The implanted carbon atoms dissolved in nickel at an elevated temperature and diffused towards to the interface between nickel film and LiNbO3 during annealing. After the nickel film fell off, the graphene material was found by Raman spectroscopy and confirmed by the Atomic Force Microscope (AFM) topographic image. Implantation combined with patterned metal film suggests the possibility to engineer two-dimensional graphene with special confinement. It also provides a valuable and novel way for integrating graphene-wafer structure for other available substrate wafer in microelectronics and photonics devices.

Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride.

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) have garnered increasing attention over the last few years due to their superior optical properties. However, despite the vast range of experimental results and theoretical calculations, the defect structure responsible for the observed emission has remained elusive. Here, by controlling the incorporation of impurities into hBN via various bottom-up synthesis methods and directly through ion implantation, we provide direct evidence that the visible SPEs are carbon related. Room-temperature optically detected magnetic resonance is demonstrated on ensembles of these defects. We perform ion-implantation experiments and confirm that only carbon implantation creates SPEs in the visible spectral range. Computational analysis of the simplest 12 carbon-containing defect species suggest the negatively charged [Formula: see text] defect as a viable candidate and predict that out-of-plane deformations make the defect environmentally sensitive. Our results resolve a long-standing debate about the origin of single emitters at the visible range in hBN and will be key to the deterministic engineering of these defects for quantum photonic devices.

Effect of Device Dimensions, Layout and Pre-Gate Carbon Implant on Hot Carrier Induced Degradation in HKMG nMOS Transistors

The hot carrier (HC) induced degradation has become a major concern in advanced CMOS technologies because of non-scalable $\text{V}_{\mathrm{ DD}}$ . In this work, we have shown that the HC induced degradation in gate-first HKMG nMOS transistors can be modulated by optimizing the device width, lanthanum capping layer thickness, and pre-gate carbon (C) implant. The physics responsible for these observations are investigated and attributed to the reduction in the number of defects (traps) in hafnium oxide (HfO2) and reduction in carrier injection into these defects. It is also shown that the HC performance of these transistors could be further improved by increasing the active-to-active spacing.

Application of nanostructured carbon implants in surgical treatment of transverse flat feet

This article discusses the modern method of treatment of transverse flat feet using carbon nanostructured implants. The characteristic features of the installation, recovery period, features of consolidation, cosmetic and functional results are analyzed. Based on the research, the disadvantages of the method, its characteristics and features were identified, and the results were compared with the data stated by the implant manufacturer

Effect of copper surface modification applied by combined modification of metal vapor vacuum arc ion implantation and laser texturing on anti-frosting property

Heat transfer deterioration due to frost accumulation on metallic surfaces provided motivation for development of protective barriers that could effectively repel water in many forms. Currently, extensive attention has focused on superhydrophobic surfaces which have been found to be effective in reducing droplets condensation and frost accumulation. The combined modification using nanosecond laser and metal vapor vacuum arc (MEVVA) ion implantation of carbon is applied to the copper surface. The results revealed that the increased proportion of carbon content contribute to the increase of surface hydrophobicity, the contact angle of the combined surface was 152.1° ± 1° and the rolling angle was 6.7° ± 1°, which exhibited a superhydrophobic character, without thermal conductivity deterioration. The processes of droplet condensation, freezing and the frosting of three kinds of surfaces (rough #1, combined surface modification #2, silanization coating #3) have been examined. The combined surface can delay the freezing process to some extent. Compared with rough copper surface, combined surface had sparse frost structure and the growth of frost could be delayed by 43% when the frost thickness was 1.5 mm. Thus, the method of combined surface shows a great advantage of frost inhibition applicability.