Effect Of Implantation Dose Research Articles

Molecular dynamics simulation of ion-implanted single-crystal 3C-SiC nano-indentation

To improve the machinability of the brittle material 3C-SiC, a new method of ion implantation surface modification is proposed. Molecular dynamics simulations were employed to investigate the mechanical properties and defect evolution of ion-implanted single-crystal 3C-SiC under nano-indentation. The effects of implantation dose, implantation energy, and implantation angle on the force, dislocation, hardness, and elastic modulus were discussed. The results revealed that ion implantation can reduce the hardness and elastic modulus, and improve the plasticity. Besides, the nucleation of dislocation is suppressed by ion implantation. It showed that the higher the implantation dose, the lower the force, the lower the hardness and elastic modulus, whereas those of implantation energy were the opposite. Therefore, the optimum implantation dose and energy can be obtained by comparing the above characteristics. Moreover, the channel effect was revealed under different implantation angles. Finally, through theoretical model analysis, it demonstrated that ion implantation affects the direction and size of normal stress. Thus, this method is favorable to material advanced manufacturing processes for enhancing the plasticity of the brittle single-crystal SiC.

Structural, Optical, and Magnetic Properties of Ag+, Mn+ and Ar+ Ions Implanted Zno Thin Films: Effect of Implantation Dose and Stopping Energy

Structural, Optical, and Magnetic Properties of Ag+, Mn+ and Ar+ Ions Implanted Zno Thin Films: Effect of Implantation Dose and Stopping Energy

Structural, optical, and magnetic properties of Ag+, Mn+ and Ar+ ions implanted ZnO thin films: effect of implantation dose and stopping energy.

Herein, we systematically studied the effect of various excitation processes on the structural, optical, and magnetic properties of ZnO films implanted with 80 keV Ar+, 110 keV Mn+, and 190 keV Ag+ ions. Four different doses of 1 × 1013, 1 × 1014, 1 × 1015, and 2 × 1016 ions per cm2 were used for implantation. It was observed that the structural, optical, and magnetic properties of the implanted samples were dominantly affected at the highest dose of 2 × 1016 ions per cm2. For lower doses, insignificant changes in these properties were observed. A comparison of various processes involved in the implantation process shows that both the electronic excitation and nuclear excitation processes are responsible for the changes in the structural, optical, and magnetic properties of the implanted ZnO films.

Effect of nitrogen ion implantation on phases, crystallization behaviors and magnetic properties of amorphous Fe-Si-B ribbons

Abstract Nitrogen ion implantation is employed to improve the soft magnetic properties of commercial amorphous Fe-Si-B ribbons. The effects of implantation dose and acceleration voltage on the micro-structure, crystallization behavior and magnetic properties are systematically investigated. 1 × 1016 ions cm−2 is determined to be the most suitable dose value to generate one layer with nitrogen implanted as well as keeping the ribbon amorphous. The maximum saturation magnetization of 1.69 T is obtained under this dose, which may be due to the contribution of the formed nanostructured nitride with higher magnetization. Continuing to increase the dose, the magnetization starts to decrease because of the crystallization of the amorphous matrix. Under different acceleration voltages, the structure of the Fe-Si-B ribbons keeps amorphous. Moreover, the largest magnetization is achieved at 150 kV.

Strain‐Driven Self‐Assembling of Nano‐Voids and Formation of Core–Shell Bubbles in SiSn/Si Layers

Self‐assembling of nanometer size voids in strained Sn precipitates after hot He+ ion implantation is investigated by transmission electron microscopy (TEM). It is deduced from TEM study that high‐temperature irradiation produces vacancies which is collected by compressively strained Sn precipitates enhancing out‐diffusion of Sn atoms from the precipitates. The effects of implantation dose and Sn precipitate size on void formation and Sn out‐diffusion are documented and evolution of voids into core–shell Sn‐bubbles is reported. In particular, the size of the voids increased with the implantation dose and the voids are transformed to the core–shell Sn particles after implantation of 6 × 1015 He+ cm−2. Formation of the core–shell structures is faster for Sn particles of smaller initial size. Strain‐enhanced separation of point defects along with vacancy‐assisted Sn out‐diffusion and precipitate dissolution are discussed.

Enhanced gettering of gold at end-of-range defects in high energy ion implanted silicon

We report on the gettering behavior of Au at end-of-range (EOR) defects in float-zone grown Si(111), implanted with 1.5 MeV Au 2+ ions at room temperature. The effects of implantation dose and annealing temperature on the thermal evolution of gettering behavior of EOR defects have been investigated using Rutherford backscattering spectrometry, while the microstructural evolution of Au implanted Si(111) has been studied using cross-sectional transmission electron microscopy combined with high resolution transmission electron microscopy. The gettering efficiency of EOR defects, comprising of dislocation loops, has been found to increase with increase in implantation dose up to 1.2 x 10 15 ions cm -2 , beyond which it was found to saturate at about 5 x 10 14 atoms cm -2 for annealing at 850 o C. We have observed that the gettering efficiency of the EOR defects for Au increased with increase in annealing temperature and reached 9 x 10 14 atoms cm -2 for annealing at 950 o C. The observed enhanced gettering efficiency of EOR defects is very promising for gettering applications in Si devices.

Effect of nitrogen ion implantation dose on torsional fretting wear behavior of titanium and its alloy

Various doses of nitrogen ions were implanted into the surface of pure titanium, Ti6Al7Nb and Ti6Al4V, by plasma immersion ion implantation. Torsional fretting wear tests involving flat specimens of no-treated and treated titanium, as well as its alloys, against a ZrO2 ball contact were performed on a torsional fretting wear test rig using a simulated physiological medium of serum solution. The treated surfaces were characterized, and the effect of implantation dose on torsional fretting behavior was discussed in detail. The results showed that the torsional fretting running and damage behavior of titanium and its alloys were strongly dependent on the dose of the implanted nitrogen ions and the angular displacement amplitude. The torsional fretting running boundary moved to smaller angular displacement amplitude, and the central light damage zone decreased, as the ion dose increased. The wear mechanisms of titanium and its alloys were oxidative wear, abrasive wear and delamination, with abrasive wear as the most common mechanism of the ion implantation layers.

Dependences of photoluminescence from P-implanted epitaxial Ge

A systematic investigation has been carried out to study the influence of various annealings and implantations on the photoluminescence (PL) properties of phosphorus (P)-implanted Ge epitaxial films on Si substrate. For un-capped Ge samples, rapid thermal annealing (RTA) at 700 °C for 300 seconds yields the strongest PL emission peaked at 1550 nm. The influence of employing various capping layers (i.e., SiO(2), Si(3)N(4), and α-Si ) on the PL properties has been investigated. The capping layers are found to effectively decrease the dopant loss, leading to a significant PL enhancement. Si(3)N(4) is found to be the most efficient capping layer to prevent dopant out-diffusion and thus lead to strongest PL. Furthermore, it has been found that capping layers not only enhance the PL intensities but also make PL emission peak red- and blue- shift, depending on the stress type of the capping films. The effect of implantation dose on the PL has been also investigated.

Ion Implanted SiO2 Substrates for Nucleating Silicon Oxide Nanowire Growth

AbstractWe experimentally demonstrate a simple and efficient approach for silicon oxide nanowire growth by implanting Fe+ ions into thermally grown SiO2 layers on Si wafers and subsequently annealing in argon and hydrogen to nucleate silicon oxide nanowires. We study the effect of implantation dose and energy, growth temperature, and H2 gas flow on the SiOx nanowire growth. We find that sufficiently high implant dose, high growth temperature, and the presence of H2 gas flow are crucial parameters for silicon oxide nanowire growth. We also demonstrate the patterned growth of silicon oxide nanowires in localized areas by lithographic patterning and etching of the implanted SiO2 substrates before growth. This works opens up the possibility of growing silicon oxide nanowires directly from solid substrates, controlling the location of nanowires at the submicron scale, and integrating them into nonplanar three-dimensional nanoscale device structures.

Magnetic Properties of Thin Metal-Polymer Films Prepared by High-Dose Ion-Beam Implantation of Iron and Cobalt Ions into Polyethylene Terephthalate

Thin metal-polymer composite films have been prepared by high-dose ion-beam implantation of Fe+ and Co+ ions into polyethylene terephthalate. The implantation of 40 keV ions at room temperature with doses from 2 · 1016 to 4 · 1017 cm−2 have been performed, with the ion current density of 4 μA/cm2. The effects of implantation dose on the film morphology and crystal structure have been investigated via atomic force and magnetic force microscopy and X-ray diffraction. The magnetic properties of synthesized structures have been studied by ferromagnetic resonance and with a vibrating-sample magnetometer. It was established that the properties of ion-implanted samples strongly depend on both the implantation dose and the type of implanted ions. The implantation dose at which the magnetic phase is formed for iron-implanted samples is significantly lower than that for cobalt-implanted ones. At high implantation doses due to polymer sputtering metal-containing layers are formed close to the sample surface for both ions. In this dose range the magnetic properties of implanted samples changed dramatically due to particle oxidation. The coercivity of synthesized layers reaches 180 and 300 Oe for iron- and cobalt-implanted samples, respectively.

Optical and Magnetic Properties of ZnO:V Prepared by Ion Implantation

We report on the optical and magnetic properties of the magnetic semiconductor Zn(V)O fabricated by implantation of 195 keV 51V+ ions into bulk ZnO:Al grown by a hydrothermal technique. Two sets of the samples, containing N d –N a ∼ 1015 cm−3 and 1018 cm−3, were implanted to doses of 1 × 1015 cm−2, 3 × 1015 cm−2, and 1 × 1016 cm−2. The ion implantation was performed at 573 K. To remove irradiation-induced defects, the samples were annealed in air at 1073 K. Photoluminescence (PL) measurements of Zn(V)O films were carried out at temperatures from 10 K to 300 K. The effects of implantation dose and free carrier concentration on the magnetic properties of Zn(V)O were studied using a superconducting quantum interference device magnetometer. Ferromagnetism has been observed in annealed highly conductive samples implanted to 1 × 1016 cm−2. The PL studies of ZnO bulk samples implanted with V+ have revealed that thermal annealing at 1073 K restores to a large extent the optical quality of the material. A new emission line centered at 3.307 eV has been found in the PL spectrum of the highly conductive samples implanted to the dose of 1 × 1016 cm−2, which is most probably due to complexes involving V ions.

Effect of Implantation Dose and Annealing Time on the Formation of Si Nanocrystals Embedded in Thermal Oxide

AbstractPhotoluminescence (PL) and X-ray Photoelectron Spectroscopy (XPS) are employed to study the Si nanocrystals formed in the thermal oxide by Si+ implantation. PL results estimate the size of nanocrystals and the concentration of Pb centers in the Si-SiO2 nanocrystal-matrix interfaces. It is shown that the size of Si nanocrystals increase with implantation dose. Increasing the dose from 1×1016 to 1×1017 Si+/cm2 shifts the size of nanocrystals from ~2 nm to ~3.5nm, while prolonging the annealing time from 1h to 2h has no effect on the position of PL peak. P and Ar implantations into the SiO2 films are also investigated to suggested that the PL peak is due to implant induced chemical changes rather than implant induced damage. XPS analysis shows that the concentration of Si nanocrystals increases with Si implantation dose. Research on the annealing dependence of the forming of Si nanocrystals suggests that 1000°C annealing produces larger amount of Si nanocrystals than 1100°C annealing.

Variable Energy Positron Annihilation Spectroscopy of GaNGrown on Sapphire Substrates with MOCVD

Depth profiled Doppler broadening of positron annihilation spectroscopy(DBPAS), which is also called the variable energy positron annihilationspectroscopy (VEPAS), is used in characterization of GaN grown onsapphire substrates with metal-organic chemical vapour deposition(MOCVD). The GaN film and the film/substrate interface areinvestigated. The VEPFIT (variable energy positron fit) software wasused for analysing the data, and the positron diffusion length of thesapphire is obtained. The results suggest that there is a highlydefected region near the GaN/sapphire interface. This thin dislocatedregion is generated at the film/substrate interface to relieve thestrain. Effects of implantation dose on defect formation, for theGaN/Sapphire samples, which implanted by Al+ ions, are alsoinvestigated. Studies on Al+ implanted GaN films (not includingthe interface and sapphire) have revealed that there are two differentregions of implantation damage. For the low Al+ implantationdose samples, in the region close to the surface, defects are mainlycomposed of vacancy pairs with small amount of vacancy clusters, and inthe interior region of the film the positron traps are vacancy clusterswithout micro-voids. For the highest dose sample, however, somepositron trap centres are in the form of micro-voids in the secondregion.

The effect of implantation dose on the microstructure of silicon nanocrystals inSiO2

Si nanocrystals were formed by the implantation ofSi+ intoa SiO2 film, deposited on (100) Si, followed by high-temperature annealing.Transmission electron microscopy (TEM) was used to examine the effect ofimplantation dose on the microstructure of the Si nanocrystals (Si nc) in theSiO2 film. The size and spatial distribution and concentration of the Si nc in four passivatedsamples with different implantation doses were investigated using the dark-field imagingtechnique. The thickness of all the samples was determined by electron energy-lossspectroscopy (EELS). The structure of the Si nc in all the samples was determined usingselected area electron diffraction. It was found that the average diameter of the Si ncchanges from 2.7 to 3 and to 3.3 nm for the samples with implantation doses of6 × 1016,8 × 1016 and 1 × 1017 cm−2; however, it ranges from 2 to 22 nm in the sample with an implantation dose of3 × 1017 cm−2. The size of the Si nc is comparatively homogeneous throughout thewhole implanted layer in the samples with implantation doses of6 × 1016 and 8 × 1016 cm−2, while in the samples with implantation doses of1 × 1017 and 3 × 1017 cm−2, the Si nc in the middle region of the implanted layer are bigger than those near the surface or thebottom of the layer. From TEM experimental results, the concentration of the Si nc is estimated tobe 6 × 1018,4 × 1018 and4 × 1018 cm−3 for the samples withimplantation doses of 6 × 1016, 8 × 1016 and 1 × 1017 cm−2, respectively. For the sample with an implantation dose of3 × 1017 cm−2, the concentration for the Si nc of 3 nm is around5 × 1018 cm−3; the concentration for Si nc of 6 nm is around2 × 1018 cm−3; and the concentration for the 12 nm group is about1 × 1018 cm−3. In addition, the concentration determined from TEM experiments is compared with thecalculated one. Combining the TEM results with a Monte Carlo simulation, we alsodiscuss the sputtering effect and the depth distribution of the Si ions implanted inSiO2.

Dose dependence of microstructural development of buried oxide in oxygen implanted silicon-on-insulator material

The effect of implantation dose on microstructural development of the buried oxide (BOX) of 200 keV oxygen implanted Si was studied by electron microscopy. A continuous BOX layer with a low density of Si islands was obtained for a dose of 0.45×1018 cm−2, following high temperature annealing. At a lower dose of 0.225×1018 cm−2 a layer did not form, but only disjointed, isolated, oxide precipitates developed. At a higher dose, 0.675×1018 cm−2, a continuous BOX layer with a high density of Si islands formed. Microstructures of intermediate-temperature annealed samples showed the formation of oxide precipitates at preferred depths, the morphology being dose dependent. The final microstructure of the BOX is strongly influenced by the evolution of the oxide precipitates during annealing. A qualitative mechanism is proposed for the dose-dependent behavior of BOX formation during the annealing process.

Effect of implantation dose on photoluminescence decay times in intermixed GaAs/AlGaAs quantum wells

The effect of ion implantation induced intermixing on the effective radiative lifetimes in GaAs/AlGaAs quantum wells is investigated using the technique of time-resolved photoluminescence (TRPL). Below the critical dose, the carrier lifetimes appear enhanced by the processing although no changes are discernible in the continuous wave photoluminescence (CWPL) spectra. Above the critical dose, carrier lifetimes are reduced by residual defects created in the intermixed wells by the implantation procedure. These observations demonstrate the greater sensitivity of TRPL over CWPL in detecting residual damage produced by processing quantum well material.

Dose and dose rate effects on the structure of methane plasma source ion implanted 304 stainless steel

Type 304 stainless steel was treated by methane plasma source ion implantation. The effects of implantation dose and dose rate on the microstructure have been investigated. The implantation was carried out at a target bias of −30 keV. Two different doses: 1.5 × 10 17 and 3 × 10 17 atoms cm −2, and three dose rates: 3.4, 6.8 and 15 μA cm −2 were used. Higher doses and lower dose rates favor the formation of crystalline structure in the form of Fe 2C (at 3.4 μA cm −2), or a mixture of Fe 2C and possibly Fe 3C and/or (Fe, Cr) 7C 3 (at 6.8 μA cm −2). Higher dose rates and lower doses favor the development of an amorphous structure. The mechanism of phase transformation in the implanted layer and its dependence on dose and dose rate are discussed.

Effects of implantation dose on the inhomogeneous broadening of zero phonon lines in LiF

The inhomogeneous broadening and line shape of the F 4 (1) zero phonon line in LiF at 2.366 eV, measured at 4 K, has been used to probe the environment of these defects and the presence of internal strain as a function of implantation dose. Measurements on LiF implanted with 1 MeV protons at room temperature show substantial broadening of the zero phonon line. Studies of low and high dose γ-irradiated samples are used for comparison purposes. The observed broadening in the proton implanted specimens shows irregularities which is compared with the growth and collapse of colour centre concentrations previously reported in the literature. The results suggest two regimes: a low dose region where broadening results from point defects and small point defect aggregates and a high dose region where extended defects are, to a significant extent, responsible. Line shape analysis is consistent with these conclusions.

The effects of implantation dose and anneal temperature on the layered structure and electrical properties of oxygen-ion-implanted silicon-on-insulator : Pradip K. Dutta and Sorin Cristoloveanu. Microelectron. J.22(7/8), 67 (1991)

The effects of implantation dose and anneal temperature on the layered structure and electrical properties of oxygen-ion-implanted silicon-on-insulator : Pradip K. Dutta and Sorin Cristoloveanu. Microelectron. J.22(7/8), 67 (1991)

Formation of shallow p+n junctions by implanting BF 2− ions into thin cobalt films on silicon substrates

Silicided shallow p + n junctions have been formed by implanting BF 2 + ions into a-Si/Co bilayer films on Si substrates and subsequent drive-in/silicidation. The effects of implantation dose and energy on the electrical characteristics were studied. The modulation ranges of implantation energy and dose employed to form good junctions are large for the present fabrication scheme. However, high-performance silicided shallow junctions must be optimized by using moderate implant energy and dosage. The junction depth, drive-in efficiency, dopant concentration and electrical characteristics must be compromised to achieve the goal of good shallow junctions. A silicided shallow junction formed by the implantation of 70 keV at a dose of 5 × 10 15 cm −2 and subsequently annealed at 700°C exhibited characteristics with a leakage current density lower than 0.5 nA cm −2, a forward ideality factor better than 1.01 and a junction depth of about 0.13 μm.