Oxygen Implantation Research Articles

Luminescent and electrical properties of oxygen‐implanted silicon

Light emitting diodes with an active defect‐rich region produced by oxygen implantation and a subsequent multistep annealing of silicon wafers were investigated by means of transmission electron microscopy, SIMS, capacitance voltage, deep level transient spectroscopy, electroluminescence (EL), and cathodoluminescence (CL) techniques. The properties of two groups of n‐based samples with and without thermal pre‐treatment at 1000 °C for 15 min were compared regarding their defect structure, defects electrical activity, luminescent spectra as well as the impact of prolonged intense electron irradiation. The observed difference in the properties of such groups was explained by a difference in the density and oxygen content of oxygen‐related defects. A significant distinction between EL and CL spectra at low excitation levels was found and interpreted to be due to particular defect kinds in near‐surface and the deepest layers of the implanted region. The blue shift of EL spectra upon excitation increase reported previously is explained by the increase of penetration depth of the holes and specific depth distribution of the defects of different kinds.

Oxide formation on chromium metal surfaces by low-energy oxygen implantation at room temperature

We have studied the formation of oxides on pure chromium metal surfaces by 1keV O2+ ion bombardment at room temperature (RT), using X-ray photoemission spectroscopy around Cr 2p or O 1s core-levels and the valence band photoemission. For comparison, we have also examined the oxidation mechanism of thermally oxidized Cr surfaces at RT. The results of thermal oxidation reveal the formation of a very thin, single Cr2O3 oxide with the saturation thickness of 0.7nm, obtained after exposure to 10L of O2. This layer reduces the reactivity of the surface and prevents any further adsorption or uptake of oxygen at higher oxygen doses. On the other hand, the oxygen-ion bombardment is more efficient in creating thicker Cr2O3 films with the logarithmic increase of film thickness with the implanted dose of oxygen, up to the saturation thickness of about 2.7nm. This thickness is in good agreement with the implantation kinetics of oxygen ions in Cr. We explain the observed direct logarithmic growth rate by the radiation-enhanced diffusion of Cr cations and O anions within the oxide film through the open volume defects, such as voids, created by ion bombardment.

Oxygen ion implantation induced structural modifications and electrical conductivity in glass RPC detector materials: A positron lifetime study

Resistive Plate Chamber (RPC) detector materials viz., Asahi and Saint Gobain float glasses were exposed to 500keV and 1MeV oxygen ions at diverse fluences. Positron Annihilation Lifetime Spectroscopic (PALS) investigations were carried out to explore the ion implantation induced microstructural modifications in these glasses. Positron lifetime parameters at lower ion implantation fluences suggests the breakage of SiO bonds at the regular tetrahedral sites of SiOSi and the displacement of molecules due to the formation of track inside the silicate glass structure in Asahi glass samples. In both the glasses, the reduced void size at higher ion implantation fluences indicates the increased chemical bonding between the tetrahedral sites and hence increases the short range order. The local temperature induced diffusion followed by trapping of ions in the interior glass voids is predominant at higher fluences. The microstructural modifications and electrical conductivity in both the glasses were well correlated with the measured free volume parameters. The variation in optical band gap from the UV–Vis absorption edge inferred the possibility of strain mismatch in the glass network by the elimination of defects at higher implantation fluences. This is complementary with Fourier Transform Infrared (FTIR) results.

Vacancy-induced ferromagnetism in ZnO probed by spin-polarized positron annihilation spectroscopy

We investigated the ferromagnetism of ZnO induced by oxygen implantation by using spin-polarized positron annihilation spectroscopy together with magnetization measurements. The magnetization measurements showed the appearance of ferromagnetism after oxygen implantation and its disappearance during post-implantation annealing at temperatures above 573 K. The Doppler broadening of annihilation radiation (DBAR) spectrum showed asymmetry upon field reversal after oxygen implantation. The obtained differential DBAR spectrum between positive and negative magnetic fields was well-explained with a theoretical calculation considering zinc vacancies. The disappearance of the field-reversal asymmetry of the DBAR spectrum as a result of annealing agreed with the observations of ferromagnetism by magnetization measurements. These results suggest the radiation-induced zinc vacancies to be the source of the observed ferromagnetism of ZnO.

A study of the behaviour of copper in different types of silicate glasses implanted with Cu+ and O+ ions

Glasses containing copper are promising photonic materials for lasing devices and all-optical components. It has already been shown that the oxidation state of the implants depends on many factors. This paper is going to report on one of them, i.e. the influence of the composition of a silicate glass matrix on the behaviour of the implanted Cu ions before and after a subsequent implantation of oxygen ions.Three types of silicate glasses having a different extent of cross-linking were implanted with copper ions with an energy of 330keV and a fluence 1×1016ionscm−2. Then the glasses were implanted with oxygen ions with an energy of 110keV into the same depth as the already implanted Cu ions. The concentration depth profiles of Cu in the glasses were studied by Rutherford Backscattering Spectrometry. After the implantation, the samples were characterised by optical absorption and photoluminescence spectroscopy. The samples were annealed in ambient atmosphere for 1h at 600°C, which is near the transformation temperature of those glasses. The effect of annealing on the distribution of the implants and on the absorption and emission spectra of the as-implanted glasses will be discussed as well.

Ion implantation effects of negative oxygen on copper nanowires

Copper nanowires of diameter 80 nm were synthesized in polycarbonate membrane using template technique. Samples were then implanted with 160 keV O−1 ion beam with varying particle fluence of 1 × 1012, 5 × 1012 and 1 × 1013 ions/cm2. The SRIM (Stopping and range of ions in matter) software was used to study the processes involved. Compositional analysis confirms implantation of oxygen ions and the stoichiometry of Cu:O was found to be 6:1 by weight % when implanted at 1 × 1013 ions/cm2. Scanning electron microscopy reveals no changes in morphology of nanowires on implantation. X-ray diffraction analysis showed no shifting in the ‘2θ’ position of diffraction peaks however some new diffraction peaks of oxygen were seen. Implantation with oxygen ion led to the increased crystallite size and reduced strain. The conductivity of the nanowires was found to increase linearly with the ion fluence presenting constructive effect of negative ion implantation on copper nanowires.

Corrosion, wear, and cell culture studies of oxygen ion implanted Ni–Ti alloy

To increase the biocompatibility of nickel–titanium (Ni–Ti) alloy substrates, oxygen ions have been implanted by the plasma immersion ion implantation (PIII–O) technique at low temperature without affecting the substrate properties. The implanted Ni–Ti surface is characterized for microhardness and composition. Energy‐dispersive spectroscopy and X‐ray photoelectron spectroscopy investigations show the replacement of native oxide on the alloy by a compact oxide during the implantation process. The corrosion behaviors of untreated substrate and PIII–O samples are investigated using potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid (Hanks' solution). Polarization and electrochemical impedance spectroscopy studies reveal nearly ideal capacitor behavior with better passivation characteristics for the oxygen‐implanted substrate. Sliding wear studies reveal lower friction of coefficient for the implanted layers as compared with the substrate. The bare and surface modified Ni–Ti alloy samples are evaluated for biocompatibility using osteoblast‐like cells (MG‐63). Cellular behavior in terms of cell morphology along with the viability and proliferations is evaluated by using scanning electron microscopy and in vitro cell culture assay, respectively. The results clearly show that oxygen implantation by PIII–O provides a better compatible surface for cell attachment and growth. The modified surface exhibits a higher percentage of cell viability demonstrating the enhanced biocompatibility of the oxygen‐implanted surface compared with bare Ni–Ti alloy. Copyright © 2017 John Wiley & Sons, Ltd.

The effects of oxygen plasma implantation on bipolar resistive-switching properties of copper nitride thin films

Copper nitride (CuxN) thin films were prepared by plasma ion immersion implantation (PIII) then post-processed with oxygen plasma implantation at a voltage of −1.5kV. The resistive-switching properties of the CuxN:O-based RRAM devices were studied with different oxygen implantation time from 0 to 20min. The memory cells processed with oxygen plasma implantation for 5min showed longest endurance performances, largest resistance window and highest yield. Linear fitting results of the electrical measurements indicated the formation of copper oxide (CuO) is benefit for prolonged cycle life of the CuxN based RRAM devices, while increasing Cu2O species will lead to severe performance degradation.

Ridge Waveguides and Y-Branch Beam Splitters in KTiOAsO4 Crystal by 15 MeV Oxygen Ion Implantation and Femtosecond Laser Ablation

We report on the fabrication of ridge waveguides and Y-branch beam splitters in KTiOAsO4 nonlinear optical crystal by the combination of 15 MeV oxygen (O5+) ion implantation and femtosecond laser ablation. Guiding properties were investigated at the wavelengths of 633 and 808 nm, respectively, showing high polarization sensitivity of light propagation. Splitting ratios of these beam splitters are dependent on in-coupling alignment. The simulated guiding modal distributions of splitted guided beams, which was based on a reconstructed refractive index profile, shows reasonable consistence with the measured ones. After the stepwise annealing treatment at 473 and 573 K for 1 h each, the propagation losses for these guiding structures have been reduced considerably.

Lateral Magnetically Modulated Multilayers by Combining Ion Implantation and Lithography.

The combination of lithography and ion implantation is demonstrated to be a suitable method to prepare lateral multilayers. A laterally, compositionally, and magnetically modulated microscale pattern consisting of alternating Co (1.6 µm wide) and Co-CoO (2.4 µm wide) lines has been obtained by oxygen ion implantation into a lithographically masked Au-sandwiched Co thin film. Magnetoresistance along the lines (i.e., current and applied magnetic field are parallel to the lines) reveals an effective positive giant magnetoresistance (GMR) behavior at room temperature. Conversely, anisotropic magnetoresistance and GMR contributions are distinguished at low temperature (i.e., 10 K) since the O-implanted areas become exchange coupled. This planar GMR is principally ascribed to the spatial modulation of coercivity in a spring-magnet-type configuration, which results in 180° Néel extrinsic domain walls at the Co/Co-CoO interfaces. The versatility, in terms of pattern size, morphology, and composition adjustment, of this method offers a unique route to fabricate planar systems for, among others, spintronic research and applications.

Formation of thin oxide layer on surface of copper caused by implantation of high-energy oxygen ions

Combination of neutron and X-ray reflectometry was used to study the vertical structure of 100 nm-thin copper films with implanted oxygen ions of energy E = [10-30] keV and doses D=[0.2-5.4]x$10^{16}$ $cm^{-2}$. The study shows that oxygen ion implantation with an energy of E = 30 keV leads to the formation of a 3 nm thick layer on the surface. Density and copper/oxygen stoichiometry of the observed surface layer are close to $Cu_2O$ oxide. We attribute the $Cu_2O$ oxide formation to highly mobilized copper atoms generated by stimulated ion implantation.

Enhanced Oxidation of Nickel at Room Temperature by Low-energy Oxygen Implantation

Enhanced Oxidation of Nickel at Room Temperature by Low-energy Oxygen Implantation

The effect of oxygen implantation on the corrosion and electrochemical properties of iron

Using the method of recording anode potentiodynamic curves in neutral and mildly alkaline borate buffer solutions, the corrosion and electrochemical behavior of iron-armco samples bombarded with oxygen ions is studied. It is shown by the method of X-ray photoelectron spectroscopy that, during such bombardment, implantation of oxygen into the surface layers of iron occurs. Therein, iron oxides of variable composition and various forms of adsorbed and absorbed oxygen are formed. These oxygen formations contribute to transfer of the iron surface to a more corrosion-resistant, passive state.

Single-file diffusion of oxygen ions in the compound YBa2Cu3O7−x

This paper discusses experimental data which show that with increasing thermal processing time, oxygen doping of crystals of YBa2Cu3O7−x with x > 0.65 (tetragonal phase) is characterized by two stages with substantially different kinetics. In the first (initial annealing) stage, oxygen ions enter at a faster rate with an activation energy of approximately 0.4 eV. The second (end of annealing) stage is characterized by significantly slower transport of oxygen ions with an activation energy on the order of 1 eV. The kinetics of the oxygen doping process is analyzed in terms of the time variation in the electrical resistance of the compound. It is shown that the faster transport of oxygen ions in the initial stage of the implantation process can take place along one-dimensional nonstoichiometric vacancies in a single-file diffusion mode. The final stage of oxygen ion implantation in this compound is described by an ordinary classical diffusion mechanism.

Persistent photoconductivity in oxygen-ion implanted KNbO 3 bulk single crystal

Abstract Persistent Photoconductivity (PPC) in oxygen-ion implanted KNbO 3 ([001] oriented bulk single crystals; perovskite structure; ferroelectric with a band gap of 3.16 eV) is studied in air at room temperature to prevent the degradation of its crystallinity caused by the phase transition. The residual hydrogens in un-implanted samples are estimated to be 5×10 14 cm −2 from elastic recoil detection analysis (ERDA). A multiple-energy implantation of oxygen ions into KNbO 3 is performed using energies of 200, 400, and 600 keV (each ion fluence:1.0×10 14 cm −2 ). The sheet resistance varies from >10 8 Ω/□ for an un-implanted sample to 1.9×10 7 Ω/□ for as-implanted one, suggesting the formation of donors due to hydrogen interstitials and oxygen vacancies introduced by the ion implantation. The PPC is clearly observed with ultraviolet and blue LEDs illumination rather than green, red, and infrared, suggesting the release of electrons from the metastable conductive state below the conduction band relating to the charge states of the oxygen vacancy.

(Keynote) FD-SOI: The History from Early Transistors to Today

SOI technology was initiated in the mid 60’s by the quest for radiation-hard devices. Silicon on Sapphire (SOS) was the founder of the SOI family which later attracted many other members: epitaxial overgrowth (ELO), lamp or laser-induced melting and recrystallization (ZMR), wafer bonding and etch-back (BESOI), oxygen implantation (SIMOX), porous Si (FIPOS), etc. The coexistence of numerous options meant that none was really convincing as an industrial solution. The discovery of the Smart-Cut technology in early 90’s brought the necessary industrial momentum in terms of material quality, device performance and product adaptability to a variety of IC applications. The further development of Smart Cut Technology for ultra thin Si SOI in the mid 2000’s opened the door to a manufacturing-compatible planar fully-depleted CMOS IC platform, known today as FD-SOI. The basic mechanisms in fully depleted FD-SOI MOSFETs (interface coupling, back-biasing for threshold voltage adjustment, volume inversion, residual floating-body effects, etc.) have been understood early, when the thickness of Si film and buried dielectric was still in the micrometer range. Since then, these layers become two orders of magnitude thinner, revealing additional phenomena, for example reduced short-channel effects and size quantization. The concept of full depletion spread from FD-SOI to FinFETs and nanowire FETs simply because it is the unique solution for continuing the CMOS down-scaling. This paper reviews the milestones in FD-SOI history with the key technical steps, the strategic industrial decisions, the path to becoming a mass production qualified 22/28nm platform, the formation of the corresponding ecosystem, the early adopters and the markets driving its future growth. We will give a brief story of FD-SOI with insider experience and discuss its future prospects as the ultra low-power mixed signal & CMOS platform of the Internet of Things (IoT) era.SOI technology was initiated in the mid 60’s by the quest for radiation-hard devices. Silicon on Sapphire (SOS) was the founder of the SOI family which later attracted many other members: epitaxial overgrowth (ELO), lamp or laser-induced melting and recrystallization (ZMR), wafer bonding and etch-back (BESOI), oxygen implantation (SIMOX), porous Si (FIPOS), etc. The coexistence of numerous options meant that none was really convincing as an industrial solution. The discovery of the Smart-Cut technology in early 90’s brought the necessary industrial momentum in terms of material quality, device performance and product adaptability to a variety of IC applications. The further development of Smart Cut Technology for ultra thin Si SOI in the mid 2000’s opened the door to a manufacturing-compatible planar fully-depleted CMOS IC platform, known today as FD-SOI. The basic mechanisms in fully depleted FD-SOI MOSFETs (interface coupling, back-biasing for threshold voltage adjustment, volume inversion, residual floating-body effects, etc.) have been understood early, when the thickness of Si film and buried dielectric was still in the micrometer range. Since then, these layers become two orders of magnitude thinner, revealing additional phenomena, for example reduced short-channel effects and size quantization. The concept of full depletion spread from FD-SOI to FinFETs and nanowire FETs simply because it is the unique solution for continuing the CMOS down-scaling. This paper reviews the milestones in FD-SOI history with the key technical steps, the strategic industrial decisions, the path to becoming a mass production qualified 22/28nm platform, the formation of the corresponding ecosystem, the early adopters and the markets driving its future growth. We will give a brief story of FD-SOI with insider experience and discuss its future prospects as the ultra low-power mixed signal & CMOS platform of the Internet of Things (IoT) era.

The influence of nitrogen ion implantation on the tribological properties of piston rings made of Hardox and Raex steels

The implantation of nitrogen, carbon, and oxygen can be used for enhancing the tribological properties of critical components for internal combustion engines. Hardox and Raex steels have very similar strength parameters as for steel used for piston rings in internal combustion engines. An essential criterion when selecting material for the production of piston rings is a low friction factor and a low wear index. The aim of this study was to determine the extent to which these parameters can be enhanced by nitrogen ion implantation. Samples were implanted with nitrogen ions with 65 keV energy and the fluence of implanted ions set to 1.1017 N + /cm2. Friction and wear measurements were performed on a pin-on disc stand. The results demonstrate that implantation with nitrogen ions significantly reduces the friction factor and wear of Hardox 450 and Raex 400 steels. Implantation can and should be used for enhancing the tribological properties of steel used for friction elements in internal combustion engines, particularly when heat treatment is excluded. Final elements can be subjected to implantation, as the process does not change their dimensions.

Optimization effect of annealing treatment on oxygen-implanted Nd:CNGG waveguides

Neodymium-doped calcium niobium gallium garnet (Nd:CNGG) waveguide operated at 632.8 nm is demonstrated by the 3.0-MeV oxygen-ion implantation with a fluence of [Formula: see text] ions/cm2. The annealing treatment at 300[Formula: see text]C for 45 min is carried out to optimize the waveguide quality. The dark-mode spectra are measured by the [Formula: see text]-line technique. The refractive index profiles are calculated from the effective refractive indices of the waveguide modes. The near-field intensity distributions are simulated based on the reconstructed refractive index profiles. The annealing treatment process could effectively remove unwanted defects and optimize the waveguide quality. The optical properties of the annealed waveguide are better than that of the as-implanted waveguide.

A novel mechanism of ultrathin SOI synthesis by extremely low-energy hot O+ implantation

Extremely low-energy oxygen implantations at 10 keV in silicon were challengingly performed to directly synthesize ultrathin silicon-on-insulator (SOI) structure separated by a buried oxide (BOX) layer. We quantitatively investigated the optimum condition and the formation mechanism of homogeneous and continuous stoichiometric SOI/BOX structure. In this study, oxygen ions were implanted into Si(0 0 1) substrates with keeping the temperatures at 500, 800, and 1000 °C with ion-fluences from 0.5 to ions cm−2. These samples were then postannealed at high temperatures from 950 to 1150 °C in Ar ambient for several hours. We found that ultrathin stoichiometric SOI/BOX structure with less than 20 nm thick was synthesized by oxygen implantation with an ion dose of ions cm−2 from 500 °C to 800 °C followed by annealing at a significantly low temperature of 1050 °C for 5 h. According to the RBS-channeling analysis, the crystallinity was excellent as quality as that of the SOI structure formed by a wafer-bonding method. We found that the BOX layer was finally formed around the deeper end of the oxygen distribution in the as-implanted sample, though the depth of the BOX formation was much deeper than the projected range of oxygen and the damage peak of silicon. The formation process of the SOI/BOX structure proposed so far could not be applicable to the present conditions for ultrathin SOI/BOX synthesis by extremely low-energy implantation followed by low-temperature annealing. We thus suggested a novel mechanism of the ultrathin SOI/BOX synthesis as follows. The mechanism during the thermal treatment was demonstrated that the recrystallization of the damaged Si layers induced by ion irradiation took place from the very surface with relatively less irradiation-damages toward deeper layers with sweeping interstitial oxygen atoms, and the condensed oxygen atoms finally synthesized the stoichiometric BOX layer.

Plasma etching to enhance the surface insulating stability of alumina for fusion applications

A significant increase in the surface electrical conductivity of alumina, considered one of the most promising insulating materials for numerous applications in fusion devices, has been observed during ion bombardment in vacuum due to oxygen loss by preferential sputtering. Although this is expected to cause serious limitations to insulating components functionality, recent studies showed it is possible to restore the damaged lattice by oxygen reincorporation during thermal treatments in air. These studies also revealed a correlation between conductivity and ion beam induced luminescence, which is being used to monitor surface electrical conductivity degradation and help qualify the post irradiation recovery. Work now carried out for Wesgo alumina considers oxygen implantation and plasma etching as additional methods to improve recovered layer depth and quality. Both conductivity and luminescence results indicate the potential use of plasma etching not only for damage recovery, but also as a pre-treatment to enhance material stability during irradiation.