Depth profiling of D implanted into Ti at different temperatures

Depth proliles of 6.6 keV D⁺ implanted into titanium in the temperature range between 140 K and 500 K have been studied using the D(³He, α) H nuclear reaction.

At 140 K the trapped amount is close to 100% at low doses and reaches saturation at about 2 × 10¹⁸D/cm², whereas at room temperature no saturation could be reached up to 2 × 10¹⁹ D/cm². At higher temperatures the amount decreases until no deuterium could be detected in the surface layer above 500 K.

The depth profiles are strongly dependent on temperature. At 140 K the deuterium is found in a surface layer of about 2000 Å with a maximum ratio of deuterium to metal atoms of 2.5. At room temperature a hydride layer of TiD^1.8, forms. The thickness of the hydride layer depends on deuterium dose and extends to 1.5 μm at 2 × 10¹⁹ D/cm². At higher temperatures the atom concentrations are lower and the deuterium seems to diffuse deeply into the bulk.

These results are discussed in terms of diffusion of deuterium i n Ti and titanium hydride.     

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.     

X-ray diffraction studies of silicon implanted with high-energy erbium ions

Silicon crystals after implantation of erbium ions with energies in the range 0.8–2.0 MeV and doses in the range 1×10¹²–1×10¹⁴ cm⁻² have been studied by two-and three-crystal x-ray diffraction. Three types of two-crystal reflection curves are observed. They correspond to different structural states of the implanted layers. At moderate doses (1×10¹²–1×10¹³ cm⁻²) a positive strain is observed, due to the formation of secondary radiation defects of interstitial type. An increase of the implantation dose is accompanied by the formation of an amorphous layer separating the bulk layer and a thin monocrystalline surface layer. At an implantation dose of 1×10¹⁴ cm⁻² the monocrystalline surface layer is completely amorphized. Parameters of the implantation layers are determined. A model of the transformation of structural damage is discussed. Fiz. Tverd. Tela (St. Petersburg) 39, 853–857 (May 1997)     

Sn离子注入PbTe的热电性能和结构

对碲化铅(PbTe)在室温下进行了Sn离子注入(200keV,6×10¹⁶和1×10¹⁷ion/cm²).应用电学和热学测量、X射线衍射技术(XRD)和X射线光电子能谱(XPS)研究了Sn离子注入PbTe的热电性能和注入层结构. 关键词：     

Magnetic structure of ion-implanted bubble garnets

The surface magnetic structure of bubble garnet films implanted with 80 keV Ne⁺ ions has been investigated by conversion-electron Mössbauer spectroscopy in conjunction with backscattered X-ray Mössbauer spectroscopy. For lower doses (～1–3 × 10¹⁴Ne⁺cm^-2) a ferrimagnetic component with in-plane magnetization coexists with a smaller paramagnetic phase in the implanted layer; for a dose of 5 × 10¹⁴Ne⁺cm^-2 only a paramagnetic phase is observed.     

Depth resolved structural study of heavy ion induced phase formation in Si/Fe/Si trilayer

Intermixing in Si/Fe/Si trilayer induced by 120 MeV Au ions has been studied. X-ray fluorescence provides information about the depth distribution of Fe atoms, while Mössbauer spectroscopy and XAFS provide information about the changes in the local structure. In the as-deposited film Fe layer is amorphous in nature with a significant Si content in it. Irradiation to a fluence of 1 ×10¹³ ions/cm² results in formation of non-magnetic intermixed layer with its hyperfine parameter close to those of Fe_0.5Si with CsCl structure. XAFS measurements under X-ray standing wave condition provide depth resolved structural information.     

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.     

Ion beam induced phase transformation in Fe–Mn bilayers: a Mössbauer study

Ion‐beam mixing of Fe–Mn bilayers induced by 100 keV krypton ions in the dose range (0.1-15)×10¹⁵ ions/cm²has been studied by means of conversion electron Mössbauer spectroscopy and X‐ray diffraction. The results indicate that a dose of about 1 ×10¹⁵ Kr⁺/cm² is sufficient to induce an appreciable mixing between the two atomic species. The α-Fe(Mn)solid solution presents a maximum at this dose, while at higher doses also the ? and γFe–Mn phases are formed in an appreciable amount. Heating of irradiated samples evidences the metastable character of ? phase and favours the growth of the terminal structures γ-Fe(Mn) and α-Mn(Fe) of the Fe–Mn equilibrium phase diagram.     

Depth profiling of ion-induced damage in D9 alloy using X-ray diffraction

The ion-induced depthwise damage profile in 35?MeV α-irradiated D9 alloy samples with doses of 5?×?10¹⁵?He²⁺/cm², 6.4?×?10¹⁶?He²⁺/cm² and 2?×?10¹⁷?He²⁺/cm² has been assessed using X-ray diffraction technique. The microstructural characterisation has been done along the depth from beyond the stopping region (peak damage region) to the homogeneous damage region (surface) as simulated from SRIM. The parameters such as domain size and microstrain have been evaluated using two different X-ray diffraction line profile analysis techniques. The results indicate that at low dose the damage profile shows a prominent variation as a function of depth but, with increasing dose, it becomes more homogeneous along the depth. This suggests that enhanced defect diffusion and their annihilation in pre-existing and newly formed sinks play a significant role in deciding the final microstructure of the irradiated sample as a function of depth.     

Structural and Chemical Modification in a Polymer by Metal Ion Implantation

Physical and chemical properties changes in a polymer have been studied for polycarbonate (PC) implanted with 100 keV Ni⁺ ions with varying fluence from 1 × 10¹⁴ to 1 × 10¹⁶ ions/cm². The changes in the surface morphology and composition have been observed with atomic force microscopy (AFM) and X-ray diffraction (XRD). The ions implanted induce changes in topography of PC and indicate that the roughness increases dramatically with ion fluence. Implanted metal ions shows direct evidence of compound formation on the surface. The chemical changes in the surface region have been carried out by Raman Spectroscopy and UV-VIS spectroscopy. UV-VIS absorption analysis indicates a drastic decline in optical band gap from 5.46 eV to 1.76 eV at an implanted dose of 1 × 10¹⁶ ions/cm². It could be shown that the partial destruction of chemical bonding under ion implantation leads to the creation of new amorphous and graphite-like structures, which is confirmed by Raman spectroscopy.     

Ion synthesis of copper nanoparticles in sapphire and their modification by high-power excimer laser pulses: A review

Composite layers made in sapphire by implantation of 40-keV Cu⁺ ions at a dose of 1 × 10¹⁷ cm⁻² and an ion beam current density varying from 2.5 to 10 μA/cm² are studied. It is shown that ion implantation makes it possible to synthesize a composite layer containing copper nanoparticles at the surface of the insulator. However, the nanoparticle size distribution in this layer is nonuniform. The composite layer is exposed to high-power excimer laser radiation with the aim of modifying the size and size distribution of the metal nanoparticles in it. The resulting structures are examined by Rutherford backscattering, optical reflection spectroscopy, and atomic force microscopy. It is found that the laser irradiation diminishes copper nanoparticles in the composite layer. Experimental data on laser modification may be explained by photofragmentation and/or melting of the nanoparticles in the sapphire matrix under the action of nanosecond laser pulses.     

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.     

Ni离子注入多晶ZrO2的表面电性能和结构

对氧化钇(Y₂O₃)部分稳定氧化锆(ZrO₂)样品在室温下进行了Ni离子注入(140kev,5×10¹⁵-2×10¹⁷ios/cm²)和热退火处理.应用电学测量,Rutherford背散射技术(RBS),X射线光电子能谱(XPS)和喇曼光谱方法研究了Ni离子注入多晶ZrO₂的表面电性能,注入层结构及其热退火的影响。     

Gettering of implanted Au in MeV?C implanted Si

The gettering behavior of 1 MeV?C implantation induced defects for Au (1.5 MeV, 2.2×10¹⁵ cm^-2), implanted into FZ Si(111), has been investigated using Rutherford backscattering spectrometry and cross-sectional transmission electron microscopy. The gettering efficiency of the C implanted layer has been studied as a function of C dose, annealing temperature and time. For a C dose of 2×10¹⁶ cm^-2, a 2 h anneal at 950 °C has been found to result in a gettering efficiency going beyond ?90%. Thermal stability of the gettered Au in the C implanted layer has subsequently been investigated over a temperature range of 950–1150 °C using isochronal annealing. The gettered amount has been found to be stable up to 1050 °C beyond which there is a release. We have observed nanovoids in the C implanted layer surrounded by ?-SiC precipitates along with patches of a-SiC. Up to about 1050 °C, these nanovoids act as efficient gettering centers beyond which they seem to release the trapped Au. Four distinct regimes in annealing temperature with different mechanisms for Au gettering have been observed.     

A Mössbauer study on thermal dynamics of Fe atoms in the implanted CuFe solid solution

The annealing behaviour for a supersaturated solid solution of CuFe produced by ⁵⁷Fe ions implanted into a copper film has been studied by CEMS at doses of 5×10¹⁵, 1×10¹⁶, 3×10¹⁶ and 1×10¹⁷ at/cm². During annealing the transformation of the γ- Fe phase and isolated iron atoms to the α-Fe phase was observed with a dose of 1×10¹⁶ at/cm² at about 440°C. Prior to α-Fe, a ferromagnetic phase with small field occured at h higher doses. The effects of radiation defects on hyperfine parameters and phase transformation are discussed in this paper.     

The near surface changes in boron implanted 4145 steel

Boron implanted 4145 steel was evaluated for changes in the near-surface region property such as microhardness. The surfaces when implanted with ¹¹B⁺ ions at 135 keV energy to a dose 1 × 10¹⁷ ions cm^?2 resulted in increase of microhardness for 10 to 40 gms of applied load. An increase upto 40% in microhardness could be observed in the specimen when annealed at 310δC for 3 hours. Furthermore, the effect of ion-beam induced intermixing of 250Å thin carbon film due to boron implantation was also studied for different doses ranging from 1 × 10¹⁷ to 3 × 10¹⁷ boron ions cm^?2. An increase in microhardness with applied load was observed for 1 × 10¹⁷ ions cm^?2 concentration, while hardest layer was formed at 3 × 10¹⁷ ions cm^?2 dose which practically had very little effect to 10 and 20 gms of load.     

Investigation of amorphous states of SiO2 by Raman scattering spectroscopy

The vitreous SiO₂ samples irradiated with fast neutrons at a dose of 5×10¹⁷?2.2×10²⁰ per cm² are investigated by the Raman scattering technique. It is demonstrated that the maximum of the low-frequency Raman spectrum (boson peak) shifts with an increase in the irradiation dose, and the medium-range order size decreases from 25 Å for the initial glass to 19 Å for the sample subjected to irradiation at a maximum dose. It is revealed that the fast relaxation intensity obtained from analysis of the low-frequency Raman spectra linearly correlates with the specific volume of the studied samples.     

The effect of high implant doses and high ion current densities on polyimide film properties

Ar⁺ and Ar²⁺ ions with energies of 40 and 80 keV are implanted into thin polyimide films. The implant doses and the ion current densities are varied in a wide range between 2.5×10¹⁴ and 1.5×10¹⁷ cm⁻² and between 1 and 16 μA/cm², respectively. The effect of the implantation parameters on the electrical, paramagnetic, and optical properties of the ion-modified near-surface polymer layer is studied. It is shown that the radiation-stimulated thermolysis of polyimide and its chemical constitution are responsible for a monotonic growth of the electrical conductivity of the layer with increasing ion current at a given implant dose. When the ion current density is fixed, the conductivity grows stepwise with implant dose, whereas the concentration of paramagnetic centers and the optical transmission of the modified layer decrease. The dependences observed are treated within a model of the structural reconfiguration of the polymer carbonized phase formed during the implantation.     

Electrical properties of thermal donors formed in silicon under elastic tensile stress

The electrical properties of thermal donors formed in the bulk and near-surface regions in silicon samples with (3–9) × 10¹⁷ cm⁻³ oxygen concentrations under elastic tensile stress σ of about 1 GPa have been studied. The original method allowing us to control an introduced elastic tensile stress during the thermal donor’s formation at T = 450°C by a double-crystal X-ray diffractometer has been used. The formation of thermal donors in silicon with a high oxygen concentration of 9.3 × 10¹⁷ cm⁻³ under tensile stress has been found to be less effective than in silicon with a low oxygen concentration of (3–5) × 10¹⁷ cm⁻³. Single-charged donors are formed in silicon with a low oxygen concentration under tensile stress while double-charged donors are formed in silicon with a high oxygen concentration.     

Mg+注入对GaN晶体辐射损伤的研究

在蓝宝石衬底上通过金属有机物化学气相沉积(metal-organic chemical vapor deposition，MOCVD)方法外延生长的GaN薄膜具有良好的结晶品质，χ_min达到2.00%. 结合卢瑟福背散射/沟道(Rutherford backscattering/channeling，RBS/C)和高分辨X射线衍射(high-resolution X-ray diffraction，HXRD)的实验测量，研究了不同剂量和不同角度Mg⁺注入GaN所造成的辐射损伤. 实验结果表明，随注入剂量的增大，晶体的辐射损伤也增大，注入剂量在1×10¹⁵atom/cm²以下，χ_min小于4.78%，1×10¹⁶atom/cm²是Mg⁺注入GaN的剂量阈值，超过这个阈值，结晶品质急剧变差，χ_min达到29.5%；随机注入比沟道注入的辐射损伤大，且在一定范围内随注入角度的增大，损伤也增大，在4×10¹⁵atom/cm²剂量下偏离〈0001〉沟道0°，4°，6°，9°时的χ_min(%)分别为6.28，8.46，10.06，10.85；经过700℃/10min+1050℃/20s两步退火和1000℃/30s高温快速退火后，晶体的辐射损伤都有一定程度的恢复，而且1000℃/30s高温快速退火的效果更好，晶体的辐射损伤可以得到更好的恢复. 关键词： GaN 卢瑟福被散射/沟道 高分辨X射线衍射 辐射损伤