Effect of nitrogen implantation with overlay coatings on microhardness in 4145 steel

The effect of nitrogen implantation on microhardness in 4145 steel was investigated. Practically no increase in microhardness for 10, 20 and 40 gm loads was observed in samples implanted with a dose of 6.5×10¹⁷N⁺ ions cm^?2 at 94 keV. The effect of ion-beam induced intermixing of aluminium and titanium film (400Å), due to nitrogen implantation was also studied. A noticeable increase of 15% in microhardness was observed. Annealing at temperature ∽300°C proved effective, while a decreasing trend in hardness could be observed for annealing temperatures >300°C. Furthermore, preliminary test indicated that these samples were more suitable for wear-protection.     

Modification of the magnetic properties of polyimide films by cobalt ion implantation

The magnetic characteristics of polyimide films implanted with Co⁺ ions with an energy of 40 keV in the dose range D = 2.50 × 10¹⁶?1.25 × 10¹⁷ cm^?2 at ion current densities j = 4, 8, and 12 μA/cm² have been investigated. It has been shown that, at implantation doses of less than 5 × 10¹⁶ cm^?2, the superparamagnetic properties of modified samples are described by the Langevin equation. At higher doses, there is an intercluster interaction. It has been found that, with an increase in the ion current, the cluster size decreases. The sizes of the formed clusters are determined and vary in the range from 3.9 to 11.0 nm, depending on the implantation dose.     

N+ Implantation-Induced Surface Hardening of Poly (Allyl Diglycol Carbonate) Polymer

The effect of 100 keV N⁺ ions implantation on the surface structure and hardness of poly (allyl diglycol carbonate) (CR-39) polymer was studied. The surface hardness of virgin and implanted CR-39 specimens was determined using a Knoop microhardness test. The surface hardness was found to be enhanced after implantation, e.g., becoming eight times higher at a load of 9.8 mN, for a dose of 2 × 10¹⁶ ions cm^?2. The change in bonding and surface structure of the CR-39 polymer due to implantation was studied using the specular reflectance Fourier transform infrared (FTIR) technique. The disordering produced in the implanted matrix was estimated using the Urbach edge method from the UV-Visible absorption spectra. The relationship of surface hardening with the chemical and structural changes was explored     

Metallic alloy precipitates in high dose indium implanted MgO

Abstract

MgO implanted at room temperature with 150keV In⁺ ions and doses ranging from 10¹⁵ to 10¹⁷ ions cm^?2 was studied by optical absorption and transmission electron microscopy (TEM). Creation of defects in the anionic sublattice (F-, F⁺-, F₂-centers) and in the cationic sublattice (V^?-centers) are observed. Subsequent annealings of the implanted crystals have shown different behaviours depending on the implanted dose. For medium dose (2 × 10¹⁶ ions cm^?2), the formation of In³⁺ species seems to be the preponderant phenomenon. At higher dose (8 × 10¹⁶ ions cm^?2), metallic precipitates are formed between 400 and 700°C. The identification of these precipitates has been achieved using TEM: they are formed of a metallic alloy Mg₃In with a hexagonal structure and their orientation relationship with respect to the MgO matrix is: (0001)Mg₃In//(111)Mgo and [1120]_Mg3In// [l10]MgO.     

Formation of bubbles and blisters in hydrogen ion implanted polycrystalline tungsten

ABSTRACT

Tungsten (W) has been regarded as one of the most promising plasma facing materials (PFMs) in fusion reactors. The formation of bubbles and blisters during hydrogen (H) irradiation will affect the properties of W. The dependence of implantation conditions, such as fluence and energy, is therefore of great interest. In this work, polycrystalline tungsten samples were separated into two groups for study. The thick samples were implanted by 18?keV H₃⁺ ions to fluences of 1?×?10¹⁸, 1?×?10¹⁹ and 1?×?10²⁰ H⁺/cm², respectively. Another thick sample was also implanted by 80?keV H₂⁺ ions to a fluence of 2?×?10¹⁷ H⁺/cm² for comparison. Moreover, the thin samples were implanted by 18?keV H₃⁺ ions to fluences of 9.38?×?10¹⁶, 1.88?×?10¹⁷ and 5.63?×?10¹⁷ H⁺/cm², respectively. Focused ion beam (FIB) combined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for micro-structure analysis, while time-of-flight ion mass spectrometry (ToF-SIMS) was used to characterize the H depth profile. It is indicated that bubbles and blisters could form successively with increasing H⁺ fluence. H bubbles are formed at a fluence of ～5.63?×?10¹⁷ H⁺/cm², and H blisters are formed at ～1?×?10¹⁹ H⁺/cm² for 18?keV H₃⁺ implantation. On the other hand, 80?keV H₂⁺ ions can create more trapping sites in a shallow projected range, and thus enhancing the blisters formation with a relatively lower fluence of 2?×?10^17?H⁺/cm². The crack-like microstructures beneath the blisters are also observed and prefer to form on the deep side of the implanted range.     

Changes in Structural and Optical Properties of Polycarbonate Induced by Ag+ Ion Implantation

Transparent polycarbonate samples were implanted with 1 MeV Ag⁺ ions to various doses ranging from 5 × 10¹⁴ to 3 × 10¹⁶ ions cm^?2 with a beam current density of 900 nA cm^?2. Modification in the structure of polycarbonate as a function of the implantation fluence was investigated using micro-Raman spectroscopy, glancing angle X-ray diffraction, and UV-Vis spectroscopy. Raman spectroscopy pointed toward the formation of graphite structures/clusters due to the ion implantation. UV-Vis absorption analysis suggests the formation of a carbonaceous layer and a drastic decrease in optical band gap from 4.12 eV to 0.50 eV at an implanted dose of 3 × 10¹⁶ ions cm^?2. The correlation between the decrease in band gap and the structural changes is discussed.     

Silicon negative ion implantation induced vacancy defects in thermally grown SiO2 thin films

ABSTRACT

Thermally grown SiO₂ thin films on a silicon substrate implanted with 100?keV silicon negative ions with fluences varying from 1?×?10¹⁵ to 2?×?10¹⁷ ions cm^?2 have been investigated using Electron spin resonance, Fourier transforms infrared and Photoluminescence techniques. ESR studies revealed the presence of non-bridging oxygen hole centers, E′-centers and P_b-centers at g-values 2.0087, 2.0052 and 2.0010, respectively. These vacancy defects were found to increase with respect to ion fluence. FTIR spectra showed rocking vibration mode, stretching mode, bending vibration mode, and asymmetrical stretching absorption bands at 460, 614, 800 and 1080?cm^?1, respectively. The concentrations of Si–O and Si–Si bonds estimated from the absorption spectra were found to vary between 11.95?×?10²¹ cm^?3 and 5.20?×?10²¹ cm^?3 and between 5.90?×?10²¹ cm^?3 and 3.90?×?10²¹ cm^?3, respectively with an increase in the ion fluence. PL studies revealed the presence of vacancies related to non-bridging oxygen hole centers, which caused the light emission at a wavelength of 720?nm.     

Spatial distribution of defects produced by boron ion implantation of silicon

A simple technique for the study of the spatial distribution of the damage produced by ion implantation of silicon has been developed. The damage depth distribution for 40 keV boron ions in silicon has been studied at irradiation doses from 7 × 10¹¹ to 3.9 × 10¹⁴ ions/cm² and the relative defect peak depth R _d/R _p = 0.85 determined. An increase of layer conductivity as the surface part of the implanted layer is removed has been revealed. This effect is caused by the presence of radiation defects in the surface region of the layer. The “electrical” cluster diameter is about 28 A and the overlapping cluster dose is close to 1 × 10¹³ ions/cm².     

Effects of silicon negative ion implantation in semi-insulating gallium arsenide

ABSTRACT

In the present work, effects of silicon negative ion implantation into semi-insulating gallium arsenide (GaAs) samples with fluences varying between 1?×?10¹⁵ and 4?×?10¹⁷?ions?cm^?2 at 100?keV have been described. Atomic force microscopic images obtained from samples implanted with fluence up to 1?×?10¹⁷?ion?cm^?2 showed the formation of GaAs clusters on the surface of the sample. The shape, size and density of these clusters were found to depend on ion fluence. Whereas sample implanted at higher fluence of 4?×?10¹⁷?ions?cm^?2 showed bump of arbitrary shapes due to cumulative effect of multiple silicon ion impact with GaAs on the same place. GXRD study revealed formation of silicon crystallites in the gallium arsenide sample after implantation. The silicon crystallite size estimated from the full width at half maxima of silicon (111) XRD peak using Debye-Scherrer formula was found to vary between 1.72 and 1.87?nm with respect to ion fluence. Hall measurement revealed the formation of n-type layer in gallium arsenide samples. The current–voltage measurement of the sample implanted with different fluences exhibited the diode like behavior.     

The electrical behaviour of abrupt ion implanted and diffused P+N junctions

Abstract

Results are reported of measurements of the properties of diodes formed by ion implantation, and for comparison boron diffused P⁺N diodes of similar area close by on the same chip. The four group III acceptor impurities were implanted separately to a dose of 5 × 10¹⁵ ions/cm² at room temperature into similar samples of suitably masked silicon. Boron ions were also implanted at liquid nitrogen temperature and 450°C. Annealing was limited to a maximum temperatare of 550 °C.

Measurements have been made of sheet resistance, forward and reverse I-V characteristics (from 10^?9 amps/cm²), reverse breakdown voltage, noise, minority carrier storage time and junction series resistance.

The bulk properties of boron implanted diodes were found to be reproducible. The introduction of recombination centres by implantation is the major factor influencing variation in these properties between one implantation condition and another. Changes in surface oxide conditions probably affect reverse leakage currents and breakdown voltages.

The properties of boron implanted diodes are considered suitable for applications such as the MOSFET, and are superior to those of the AI, Ga and In implanted diodes.     

CEMS study on aluminium implanted iron

Up to now a great deal of investigations in ion beam mixing of iron-aluminium layers are known. However, the easier way to produce such layers by direct implantation of aluminium ions in iron is less studied. In the present work aluminium implanted iron layers are studied. Iron samples were implanted with aluminium ions at 50, 100, and 200 keV, respectively, with doses between 5×10¹⁶ and 5×10¹⁷ cm⁻². Independent of energy, at doses up to 2×10¹⁷ cm⁻², besides alpha iron further magnetic fractions with a Fe₃Al-like structure are formed while at a dose of 5×10¹⁷ cm⁻² amorphous nonmagnetic components are formed.     

Some studies of BF2 and B+F implanted Silicon

Ion-implanted shallow junctions have been investigated using BE₂ (molecular ions) by the anodic oxidation method coupled with a four-point probe technique. BF₂ ions were implanted through screen oxide at doses of 3–5 × 10¹⁵ ions/cm² and energies of 25 and 45 keV which is equivalent to 5.6 keV and 10 keV of boron ions. The effect of energy, dose and annealing temperature on shallow junctions is presented in this paper. The shallow junctions in the range of 0.19 μm to 0.47 μm were fabricated.

The effect of fluorine on sheet resistivity of boron implanted silicon at various doses, treated with two-step and three-step annealing, is also presented for comparison in the paper.     

Enhancement of third-order nonlinearity in Ag-nanoparticles-contained chalcohalide glasses

Ag-nanoparticles were embedded in 56GeS₂?C24Ga₂S₃?C20KBr chalcohalide glass with average size varying from 100 to 300 nm. A large femtosecond optical Kerr effect indicated an enhancement of third-order optical nonlinearity due to Ag-nanoparticles observed by AFM images. Among these Ag-nanoparticles-embedded chalcohalide glass samples, the sample (c) with the second largest implanting dose 1 × 10¹⁷ ions/cm² showed the largest value of ??⁽³⁾ 5.34 × 10^?13 esu, which was ten times larger than that of the substrate. The nonlinear relation between the implanted dose and third-order optical nonlinearity is strongly related to the intrinsic local field and Ag-nanoparticles interaction in the glasses.     

Phase analysis in α-Fe after high-dose Si ion implantation by depth-selective conversion-electron Mössbauer spectroscopy (DCEMS)

Si⁺ ions of 50 keV in energy were implanted into α-Fe (95% ⁵⁷Fe) with a nominal dose of 5 × 10¹⁷ cm^?2 at 350°C. The depth distribution of the Fe-Si phases formed by ion implantation after annealing at 300 and 400°C for 1 h was studied quantitatively by depth-selective conversion-electron Mössbauer spectroscopy (DCEMS). Ordered Fe₃Si and ε-FeSi was observed.     

钴离子注入对二氧化钛晶体的结构和光学性能的影响

采用离子注入法制备了钴离子掺杂的金红石相TiO₂样品;离子注入能量、注量分别为40 keV(1×10¹⁶cm^-2),80 keV(5×10¹⁵,1×10¹⁶,5×10¹⁶,1×10¹⁷cm^-2),120 keV(1×10¹⁶cm^-2). 通过XRD,XPS和UV-Vis等手段对掺杂前后样品的结构和光学性能进行了表征,分析了掺杂元素在金红石TiO₂中的存在形式. XRD测试表明随着注入能量的增加晶体的损伤程度增加. UV-Vis测试表明掺杂后所有样品在可见光区的吸收增强; 并且随着注量的增加,注量为5×10¹⁵cm^-2到5×10¹⁶cm^-2范围内注入样品的光学带隙逐渐变小. 关键词： 钴 二氧化钛 离子注入 掺杂     

Epitaxial growth of silicon on silicon implanted with iron ions and optical properties of resulting structures

The method of ultrahigh-vacuum low-temperature (T = 850°C) purification of silicon single crystals having the (100) and (111) orientation and implanted with low-energy (E = 40 keV) iron ions with various doses (Φ = 10¹⁵?1.8×10¹⁷ cm^?2) and subjected to pulsed ion treatment (PIT) in a silicon atom flow has been tested successfully. The formation of semiconducting iron disilicide (β-FeSi₂) near the surface after PIT is confirmed for a Si(100) sample implanted with the highest dose of iron ions. The possibility of obtaining atomically smooth and reconstructed silicon surfaces is demonstrated. Smooth epitaxial silicon films with a roughness on the order of 1 nm and a thickness of up to 1.7 μm are grown on samples with an implantation dose of up to 10¹⁶ cm^?2. Optical properties of the samples before and after the growth of silicon layers are studied; the results indicate high quality of the grown layers and the absence of iron disilicide on their surface.     

锆离子注入锆-4合金缺陷的慢正电子研究

采用慢正电子束多普勒展宽谱研究了Zr离子注入Zr-4合金产生的缺陷及其退火回复行为，发现经过大于离子注入剂量为1×10¹⁶cm^-2的样品所产生的缺陷在注入过程中已经回复，而对剂量为1×10¹⁵cm^-2样品做300℃退火处理，其缺陷基本回复，得出合金缺陷回复能较低的结论. 考虑到材料的缺陷含量越高，其抗腐蚀性能越差，在辐照环境下通过给材料保持一定温度，即可使其缺陷得到较好回复，从而提高材料的抗腐蚀性能.     

YIG formation in annealed iron implanted YAG

YAG and YIG crystals implanted respectively with 100 keV⁵⁷Fe²⁺ ions (1 × 10¹⁷ ions.cm^?2) and 50 keV²⁷Al ions (1.1 × 10¹⁷ ions.cm^?2) have been studied by conversion electron Mössbauer spectroscopy (CEMS) directly after implantation and after annealings in air at temperatures up to 1100°C. In both as-implanted samples iron is found mainly in three states: Fe²⁺, Fe³⁺ and small metallic precipitates. Annealing behaviour is divided into two stages: (i) up to 400°C the iron has become completely oxidized and (ii) between 400 and 850°C the epitaxial regrowth of the implanted layer takes place. During this process a part of iron ions are incorporated into octahedral and tetrahedral sites, thus making a Y₃ (Al Fe)₅ O₁₂ compound. The remaining iron part precipitates in the form of Fe₂O₃ particles.     

Dynamic behavior of implanted nitrogen in zirconium at various stages of implantations

Abstract

Depth profiles of nitrogen implanted into Zr with an energy of 50 keV were calculated by dynamic SASAMAL code with three different assumptions for the diffusion of excess atoms over stoichiometry, i.e., ‘no diffusion', ‘both-sides-diffusion’ and ‘upward-diffusion'. To distinguish nitrogens implanted certain stage of implantations, alternate implantations of ¹⁵N and ¹⁴N were used. The results were compared with the experimental results by the resonance nuclear reaction analysis, NRA. For ¹⁵N implantation with fluences from 1 × 10¹⁷ to 1 × 10¹⁸ ions/cm², the calculated results with ‘upward-diffusion’ agreed very well with the NRA results for all fluences. For the depth profile of pre-implanted ¹⁵N (1 × 10¹⁷ ions/cm²), which was changed by the subsequent ¹⁴N implantation with fluences of 1 ～ 10 × 10¹⁷ ions/cm², the agreement with the NRA results was satisfactory until the ¹⁴N fluence did not exceed 5 × 10¹⁷ ions/cm², but for higher fluences, the retained probabilities of ¹⁵N obtained by the ‘upward-diffusion’ code were too low compared with the experimental value obtained by NRA. For the depth profiles of ¹⁵N (1 × 10¹⁷ ions/cm²) implanted following after implantations of ¹⁴N with fluences of 1 ～ 10 × 10¹⁷ ions/cm², the agreement with the NRA results was quite good for all ¹⁴N fluences. It is concluded that the approximation of ‘upward-diffution’ is proper satisfactorily for the treatment of atoms implanted at the final stage of implantations, but a problem is left for the treatment of atoms implanted at the early stage of implantations.