The influence of incidence angle on disorder production in Cl and Ar ion implanted Si

Abstract

Cl and Ar ions have been implanted, at 30 keV and at various incidence angles, into Si substrates maintained at room temperature during implantation. Implantation induced Si disorder was measured using RBS channelling. The effects upon disorder of various incidence angles were studied over a fluence range of 10¹²-6·10¹⁵ ions·cm^?2

The results show that, at low fluences Cl and Ar ion implantations generate a bimodal disorder-depth profile, whilst at higher fluences measurements of amorphised layer thickness as a function of ion incidence angle allow values of the standard deviation of the disorder profile parallel and transverse to the ion beam direction for each ion to be obtained with good agreement to theoretical predictions. The disorder-fluence behaviour under these conditions is ion species independent.     

Crystalline to amorphous transformations in ion implanted GaP

Abstract

The amorphization process of GaP by ion implantation is studied. The samples of 〈111〉 oriented GaP were implanted at 130 K with various doses 5 × 10¹³-2 × 10¹⁶ cm^?2 of 150 keV N⁺ ions and with the doses of 6 × 10¹²-1.5 × 10¹⁵ cm^?2 of 150 keV Cd⁺ ions. Room temperature implantations were also performed to see the influence of temperature on defect production. Rutherford backscattering and channelling techniques were used to determine damage in crystals. The damage distributions calculated from the RBS spectra have been compared with the results of Monte-Carlo simulation of the defect creation.

The estimated threshold damage density appeared to be independent on ion mass and is equal 6.5 × 10²⁰ keV/cm³. It is suggested that amorphization of GaP is well explained on the basis of a homogenous model.     

Molecular dynamics study of ion transport in CaF2(10 mol % LaF3)

Abstract

We present the results of a molecular dynamics study of CaF₂(10 mol % LaF₃). No diffusion of fluorine ions is observed in pure CaF₂ below the transition temperature (T_C ≈ 1460K) to the fast-ion phase. However, doping with La³⁺ ions promotes fluorine ion diffusion in this temperature range, and tends to suppress it above T_C. Various ion migration mechanisms are discussed.     

Carrier removal by implanted IONS in GaAs

Abstract

A model for calculation of the range distribution of energetic ions with taking into account the channeling effect is proposed. The measurement of the depth distributions of boron ions in silicon crystals implanted at 13.6 and 91 MeV revealed significant difference between the measured and the calculated range profiles when the channeling effects have not been included in the calculation. In spite of deminishing the critical angles of channeling with growing ion energy the probability of the capture of ions into the channeling regime is significant in case of high energy implantation even when the incident angles are 7–10° off the main crystallographic directions.     

Peculiarities of heavy ion channeling

Abstract

Depth distributions of implanted Mg⁺- and Ca⁺-ions and the corresponding radiation damage were studied for different channeling orientations of silicon crystals. The shape of the implantation profiles is discussed by using simple models for dechanneling and energy loss processes. A correlation between dechanneling, damage production and depth distributions of the channeled ions could be observed. This correlation is seen by the maxima shifts in damage and implanted ion distributions between channel and random incidence.     

The loss of boron in ultra-shallow boron implanted Si under heavy ion irradiation

Heavy ion impact has been known to cause a loss of light elements from the near-surface region of the irradiated sample. One of the possible approaches to a better understanding of the processes responsible for the release of specific elements is to irradiate shallow-implanted samples, which exhibit a well-known depth distribution of the implanted species. In this work, the samples studied were produced by implantation of Si<1 0 0>wafers with ¹¹B at implantation energies of 250 and 500 eV and fluence of 1.0×10¹⁵ atoms/cm ². Elastic Recoil Detection Analysis was applied to monitor the remnant boron fluence in the sample. Irradiation of the samples by a 14.2 MeV ¹⁹F ⁴⁺ beam resulted in a slow decrease of boron remnant fluence with initial loss rates of the order of 0.05 B atom per impact ion. Under irradiation with 12 MeV ³²S ³⁺ ions, the remnant boron fluence in Si decreased exponentially with a much faster loss rate of boron and became constant after a certain heavy ion irradiation dose. A simple model, which assumes a finite desorption range and corresponding depletion of the near-surface region, was used to describe the observations. The depletion depths under the given irradiation conditions were calculated from the measured data.     

氮团簇离子注入单晶硅的光致发光谱研究

氮团簇离子N⁺₁₀注入单晶硅直接诱发其表层转化为纳米晶结构, 导致光学性质发生显著变化. 在250—320nm波段的紫外光激励下,在330—500nm光区出现明显的光发射带,并在360nm附近产生强度极高、单色性良好的发射峰,其强度达到N⁺注入试样或基底的5倍,是N⁺₂注入试样的1.5倍. 在可见光区的730nm附近和近红外区的830nm附近也出现发光带. 所有上述发光都非常稳定,可长时间保持其发 关键词： 光致发光 团簇离子注入 硅单晶 纳米晶结构     

低能离子注入植物种子的深度分布及生物效应机理研究

采用四种物理测量方法：扫描电子显微镜和能量色散x射线分析，质子激发x荧光分析，双光子激光扫描显微技术和正电子湮没技术测定了能量为200keV V⁺ 注入干花生种 子的深度分布.测量结果表明，注入的低能离子在干种子花生内的深度远比TRIM95的理论计算值为高.对低能离子注入植物种子后的生物效应的机理进行了讨论. 关键词： 低能离子注入 植物种子 深度分布 生物效应机理     

The effect of annealing ambient on carrier recombination in boron implanted silicon

The selection of either an oxidising or inert ambient during high temperature annealing is shown to affect dopant activation and electron–hole recombination in boron implanted silicon samples. Samples implanted with B at fluence between 3 × 10¹⁴ cm^–2 to 3 × 10¹⁵ cm^–2 are shown to have lower dopant activation after oxidation at 1000 °C compared to an equivalent anneal in an inert ambient. In addition, emitter recombination is shown to be up to 15 times higher after oxidation compared with an inert anneal for samples with equivalent passivation from deposited Al₂O₃ films. The observed increase in recombination for oxidised samples is attributed to the enhanced formation of boron‐interstitial defect clusters and dislocation loops under oxidising conditions. It is also shown that an inert anneal for 10 minutes at 1000 °C prior to oxidation has no significant impact on sheet resistance or recombination compared with a standard oxidation process.

     

Effect of primary oxygen ion implantation on SIMS depth profiling in glasses

The influence of the primary oxygen ion implantation on SIMS in-depth profiles in halide and chalcogenide glasses was examined. Various behaviours of particular profiles were generally explained in terms of the chemical affinity of analysed reactants and modifications of the glass structure induced by primary ions.     

磷离子注入纳米金刚石薄膜的n型导电性能与微结构研究

系统研究了磷离子注入并在不同温度退火后的纳米金刚石薄膜的微结构和电学性能.研究表明,当退火温度达到800 ℃以上时,薄膜呈良好的n型电导.Raman光谱和电子顺磁共振谱的结果表明,薄膜中金刚石相含量越高和完整性越好,薄膜电阻率越低. 这说明纳米金刚石晶粒为薄膜提供了电导.1000 ℃退火后,薄膜晶界中的非晶石墨相有序度提高,碳悬键数量降低,薄膜电阻率升高.薄膜导电机理为磷离子注入的纳米金刚石晶粒提供了n型电导,非晶碳晶界为其电导提供了传输路径. 关键词： 纳米金刚石薄膜 n型 磷离子注入     

The variation of defect damage with depth in molybdenum irradiated with 2MeV nitrogen ions

Transmission electron microscopy has been used to examine the damage produced in specimens of high purity molybdenum following irradiation with 2 MeV nitrogen ions in the Van de Graaff accelerator. A simple electropolishing technique was developed to allow the defect damage to be examined at different depths on a single specimen. Some results are presented here for specimens irradiated in the range 600–800°C, together with theoretical predictions of the nitrogen range and the variation of displacement damage with range, The experimental results show that the defect damage to the lattice results in a structure of dislocation loops, interstitial in nature, whose size drops with distance from the bombarded surface and whose concentration increases. Nevertheless the retained defect damage, measured by integrated loop area, agrees reasonably with the theoretical variation of displacement damage with range while the increase in loop concentration with depth coincides with the variation in ratio of nitrogen concentration to displacement damage. This latter result agrees with the hypothesis that the nucleation of damage is controlled to a large extent by the ratio of impurity atoms to displaced atoms.     

氧离子注入纳米金刚石薄膜的微结构和电化学性能研究

在纳米金刚石薄膜中注入剂量为1012cm-2的氧离子,并进行700,800,900和1000?C的真空退火处理,系统研究薄膜的微结构和电化学性能结果表明,氧离子注入未退火(O120)和氧离子注入1000?C退火(O121000)电极的电势窗口分别为4.60 V和3.61 V,远大于其他电极的电势窗口,并且这两个样品的电极传质效率较高,说明氧离子注入和高温退火有利于提高电极的传质效率.红外光谱测试表明,样品O120和O121000的表面没有碳氢基团终止层,而其他样品均含有氢终止层,说明氧离子注入和高温退火破坏了薄膜表面含碳氢基团的氢终止层,提高了薄膜的电化学性能Raman光谱测试结果表明,金刚石含量较高、内应力较小和非晶石墨相无序化程度较大的样品具有较好的电化学性能;并且薄膜晶界处的非晶碳的团簇数量或者尺寸减小,样品的电化学性能提高.     

Study of the lateral distribution of neodymium ions implanted in silicon

Due to the need to reduce electronic device sizes,it is very important to consider the depth and lateral distribution of ions implanted into a crystalline target.This paper reports that Nd ions with energies of 200 keV to 500 keV and dose of 5×10 15 ions/cm 2 are implanted into Si single crystals at room temperature under the angles of 0,30,and 45,respectively.The lateral spreads of 200 keV-500 keV Nd ions implanted in Si sample are measured by Rutherford backscattering technique.The results show that the measured values are in good agreement with those obtained from the prediction of SRIM2010 codes.     

Investigation of the lateral spread of erbium ions implanted in silicon crystal

The erbium ions at energy of 400 keV and dose of 5×10 15 ions/cm 2 were implanted into silicon single crystals at room temperature at the angles of 0,45 and 60.The lateral spread of 400 keV erbium ions implanted in silicon sample was measured by the Rutherford backscattering technique.The results show that the measured values were in good agreement with those obtained from the prediction of TRIM’98 (Transport of Ions in Matter) and SRIM2006 (Stopping and Range of Ions in Matter) codes.     

磷离子注入速率对4H-SiC(0001)晶格恢复与电阻率降低的影响

高剂量的磷离子注入4H-SiC(0001)晶面，注入速率从1.0×1012到4.0×1012 P+ cm-2s-1变化，而注入剂量固定为2.0×1015 P+ cm-2。室温注入，1500oC的高温下退火。利用光荧光和拉曼谱分析注入产生的晶格损伤以及退火后的残余缺陷。通过霍耳测试来分析注入层的电学性质。基于上述测试结果，发现通过减小磷离子的注入速率，极大地减少了注入层的损伤及缺陷。考虑到室温注入以及相对较低的退火温度(1500 oC)，在注入速率为1.0×1012 P+ cm-2s-1及施主浓度下为4.4×1019 cm-3的条件下，获得了非常低的方块电阻106 Ω/sq。     

The effect of nitrogen ion implantation on tungsten surfaces

X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to study the phase, composition and chemical states of elements at the tungsten surface. The measurement results indicate that nitrogen-containing phase of tungsten were formed by nitrogen ion implantation (energy 40 keV, implantation doses of 4×10¹⁷, 8×10¹⁷ and 1.6×10¹⁸ ions/cm²). The formation of the W_x(O,N) and WN in the surface layer occurred as a result of nitrogen ion irradiation. A decrease in concentration of W_x(O,N) is observed with increasing N⁺ while that WN increases. Due to residual oxygen in the chamber WO₃ still exists at the surface of the specimen.     

Reflection of keV heavy-ion beams from solid targets. Dependence on energy and angle of incidence

Recent experimental and theoretical studies of the reflection of keV heavy-ion beams have been extended to higher energies and to non-perpendicular incidence. The reflection coefficient for Na⁺ and K⁺ ions backscattered from polycrystalline gold and silver targets has been obtained for perpendicular incidence at energies of 100–500 keV. The dependence on angle of incidence has been investigated at 30 keV for the same combinations of targets and projectiles. Effects of electronic stopping have been included in the theoretical calculations. Good agreement between the experimental results and the theoretical calculations is found.     

离子注入和固相外延制备Si1-x-yGexCy半导体薄膜

用等离子体增强化学气相淀积(PECVD)生长了200nm的SiGe薄膜,然后将C离子注入SiGe层,经两步热退火处理制备了Si1-x-yGexCy三元合金半导体薄膜.应用卢瑟福背散射(RBS),傅里叶变换红外光谱(FTIR)和高分辨率x射线衍射(HRXRD)研究了薄膜的结构和外延特性.发现C原子基本处于替代位置,C原子的掺入缓解了SiGe层的压应变 关键词： Si1-x-yGexCy薄膜 离子注入 固相外延     

Raman studies on the effect of multiple-energy ion implantation on single-crystal hexagonal boron nitride

Single energy ion implantation of hexagonal boron nitride (h-BN) at various fluences and keV energies has shown that there is a change in the local symmetry of the crystal from hexagonal to the cubic (c-BN) symmetry. These conclusions have been primarily based on Raman scattering (RS) and Fourier transform infrared spectroscopy. Transmission electron microscopy (TEM) analyses have been a challenge because the sample preparation for cross-sectional study of both the polycrystalline substrates and single-crystal material used in the study presented problems that were difficult to circumvent. A multiple-energy implant with different fluence fractions has been used to create a uniform implanted layer in the material from the surface to the end of range of the implant in this study. We report on the initial RS studies on these samples.