RECRYSTALLIZATION, IMPURITY MIGRATION AND OPTICAL ACTIVATION OF YB-IMPLANTED SILICON INDUCED BY RAPID THERMAL ANNEALING

The rapid thermal annealing temperature dependence of the recrystallization, Yb migration and its optical activation were studied for Yb-implanted silicon. For the annealing regime 800-1000-degrees-C, the Yb segregates both at the crystal/amorphous interface and at the surface, which is different from the usual segregation of Er at the crystal/amorphous interface, and the efficiency of optical activation also increases with annealing temperature. However, the amorphous layer regrows completely and no photoluminescence is observed after the annealing at 1200-degrees-C.

CHANNELING ALIGNMENT FOR EPITAXIAL LIGHT-MASS FILM ON HEAVY-MASS SUBSTRATE

A simple procedure for obtaining a background-free backscattering spectrum of a light-mass film on a heavy-mass substrate by a normal incidence/grazing exit geometry has been described. Using this method such films can be aligned rapidly and accurately, and the impurity or defect information on the films can be obtained without need for realignment. Example is given from MeV Li-3+ analysis of a deposited film of Si on a single crystal substrate of yttria-stabilized, cubic zirconia.

GROWTH OF HIGH-QUALITY GALLIUM-ARSENIDE ON HF-ETCHED SILICON (001) BY CHEMICAL BEAM EPITAXY

HF etching followed by relatively low temperature (almost-equal-to 600-degrees-C) pretreatment is shown to provide a suitable substrate for the heteroepitaxial growth of GaAs on Si(100) by CBE using TEGa and AsH3 as sources. Rutherford backscattering (RBS), photoluminescence (PL), transmission electron microscopy (TEM), and Raman measurements show the low-defect nature of the GaAs epilayer.

INDIUM OHMIC CONTACTS TO N-ZNSE

The reaction between an indium over layer and high purity MBE grown n-ZnSe chlorine doped (2x 10(18) cm-3) epilayers has been investigated using X-ray diffraction, Rutherford backscattering spectroscopy, X-ray photoelectron and Auger electron spectroscopy, and by electrical function tests (I-V and C-V). Good ohmic contacts were formed after annealing at 250 or 300-degrees-C for a few minutes in forming gas. Annealing at lower or higher temperatures resulted in higher resistance or rectifying contacts. The data show that no compounds were formed at the interface; instead In appeared to diffuse into the ZnSe. High surface doping densities appear to allow an ohmic contact, but the electrical data suggest that compensation effects are also very significant in the formation of the contact. These effects must be considered for successful formation of the ohmic contact.

REDUCTION OF CRYSTALLINE DISORDER IN MOLECULAR-BEAM EPITAXY GAAS ON SI BY MEV ION-IMPLANTATION AND SUBSEQUENT ANNEALING

Molecular beam epitaxy GaAs films on Si, with thicknesses ranging from 0.9-2.0-mu-m, were implanted with Si ions at 1.2-2.6 MeV to doses in the range 10(15)-10(16) cm-2. Subsequent rapid infrared thermal annealing was carried out at 850-degrees-C for 15 s in a flowing N2 atmosphere. Crystalline quality was analyzed by using Rutherfold backscattering/channeling technique and Raman scattering spectrometry. The experimental results show that the recrystallization process greatly depends on the dose and energy of implanted ions. Complete recrystallization with better crystalline quality can be obtained under proper implantation and subsequent annealing. In the improved layer the defect density was much lower than in the as-grown layer, especially near the interface.

IMPLANTATION ENERGY SELECTION IN MOLECULAR-BEAM EPITAXY GAAS FILMS ON SI SUBSTRATES

GaAs films made by molecular beam epitaxy with thicknesses ranging from 0.9 to 1.25-mu-m on Si have been implanted with Si ions at 1.2 MeV to dose of 1 x 10(15)/cm2. A rapid infrared thermal annealing and white light annealing were then used for recrystallization. Crystalline quality was analysed by using backscattering channeling technique with Li ion beam of 4.2 MeV. The experimental results show that energy selection is important for obtaining better and uniform recrystallized GaAs epilayers.

CERIUM SILICIDE FORMATION IN THIN CE SI MULTILAYER FILMS

Alternating layers of Si(200 angstrom thick) and Ce(200 angstrom thick) up to 26 layers altogether were deposited by electron evaporation under ultrahigh vacuum conditions on Si(100) substrate held at 150-degrees-C. Isothermal, rapid thermal annealing has been used to react these Ce-Si multilayer films. A variety of analytical techniques has been used to study these multilayer films after annealing, and among these are Auger electron spectroscopy, Rutherford backscattering, X-ray diffraction, and high resolution transmission electron microscopy. Intermixing of these thin Ce-Si multilayer films has occurred at temperatures as low as 150-degrees-C for 2 h, when annealed. Increasing the annealing temperature from 150 to 400-degrees-C for 1 h, CeSi2 forms gradually and the completion of reaction occurs at approximately 300-400-degrees-C. During the formation of CeSi2 from 150-400-degrees-C, there is some evidence for small grains in the selected area diffraction patterns, indicating that CeSi2 crystallites were present in some regions. However, we have no conclusive evidence for the formation of epitaxial CeSi2 layers, only polycrystals were formed when reacted in the solid phase even after rapid thermal anneal at 900-degrees-C for 10 s. The formation mechanism has also been discussed in combining the results of the La-Si system.

X-ray-diffraction study of quasipseudomorphic ErSi1.7 layers formed by channeled ion-beam synthesis

ErSi1.7 layers with high crystalline quality (chi(min) of Er is 1.5%) have been formed by 90 keV Er ion implantation to a dose of 1.6X10(17)/cm(2) at 450 degrees C using channeled implantation. The perpendicular and parallel elastic strain e(perpendicular to)=-0.94%+/-0.02% and e(parallel to)=1.24%+/-0.08% of the heteroepitaxial erbium silicide layers have been measured with symmetric and asymmetric x-ray reflections using a double-crystal x-ray diffractometer. The deduced tetragonal distortion e(T(XRD))=e(parallel to)-e(perpendicular to)=2.18%+/-0.10%, which is consistent with the value e(T(RBS))2.14+/-0.17% deduced from the Rutherford backscattering and channeling measurements. The quasipseudomorphic growth of the epilayer and the stiffness along a and c axes of the epilayer deduced from the x-ray diffraction are discussed.

Diamond growth by carbon ion implantation of diamond

Medium energy (5-25 keV) C-13(+) ion implantation into diamond (100) to a fluence ranging from 10(16) cm(-2) to 10(18) cm(-2) was performed for the study of diamond growth via the approach of ion beam implantation. The samples were characterized with Rutherford backscattering/channelling spectroscopy, Raman spectroscopy, X-ray photoemission spectroscopy and Auger electron spectroscopy. Extended defects are formed in the cascade collision volume during bombardment at high temperatures. Carbon incorporation indeed induces a volume growth but the diamond (100) samples receiving a fluence of 4 x 10(17) to 2 x 10(18) at. cm(-2) (with a dose rate of 5 x 10(15) at. cm(-2) s(-1) at 5 to 25 keV and 800 degrees C) showed no He-ion channelling. Common to these samples is that the top surface layer of a few nanometers has a substantial amount of graphite which can be removed by chemical etching. The rest of the grown layer is polycrystalline diamond with a very high density of extended defects.

Distributed Temperature Sensing System Based on Rayleigh Scattering BOTDA

A distributed temperature sensor based on Rayleigh scattering Brillouin optical time domain analysis (Rayleigh-BOTDA) is proposed in this paper. The sensor uses Rayleigh backscattering effect of microwave modulated pulse base sidebands as probe wave and a high sensitive photon counting detector for Brillouin signal intensity detection. Compared with a conventional BOTDA system, the Rayleigh-BOTDA effectively suppresses polarization-induced signal fluctuation resulting in improved signal intensity. The experimental scheme presented is simplified by using a single laser with one-end access. The temperature accuracy of the new sensing system was demonstrated as 1 degrees C on spatial resolution of 3 m.

快重离子辐照引起Ni/SiO2界面原子混合及相变研究

Ni/SiO2 interface were irradiated at room temperature with 308 MeV Xe ions to 1×1012,5×1012 Xe/cm2 and 853 MeV Pb ions to 5×1011 Pb/cm2,respectively.These samples were analyzed using Rutherford Backscattering Spectrometry(RBS) and X-ray diffraction spectroscopy(XRD),from which the intermixing and phase change were investigated.The obtained results show that both Xe-and Pb-ions could induce diffusion of Ni atoms to SiO2 substrates and result in intermixing of Ni with SiO2.Furthermore,1.0×1012 Xe/cm2 irradiat...中文摘要：在室温下用308 MeV的Xe离子和853 MeV的Pb离子辐照Ni/SiO2样品,用卢瑟福背散射和X射线衍射技术对样品进行了分析。通过分析Ni/SiO2样品中元素成分分布和结构随离子辐照剂量和电子能损的变化,探索了离子辐照在Ni/SiO2样品中引起的界面原子混合与结构相变现象。实验结果显示,Xe和Pb离子辐照均能引起明显的Ni原子向SiO2基体的扩散并导致界面附近Ni,Si和O原子的混合。实验观测到低剂量Xe离子辐照可产生NiSi2相,而高剂量Xe离子辐照则导致了Ni3Si和NiO相的形成。根据热峰模型,Ni原子的扩散和新相的形成可能由沿离子入射路径强电子激发引起的瞬间热峰过程驱动。

铝镁尖晶石中He离子注入引起损伤的退火行为研究

利用卢瑟福沟道背散射技术结合表面的原子力显微分析，对注He的铝镁尖晶石晶体的晶格损伤及表面形变随退火温度变化的关系进行了研究.结果表明，不同注入剂量的样品中晶格损伤和表面形变表现出显著不同的退火行为.分析认为造成损伤演化的这种差异与注入的He原子在晶体中不同的聚集状态有关.

The effects of the annealing time on helium implantation in Si

The modifications induced in silicon samples by helium implantation before and after isothermal annealing at 673 K have been investigated. The surface morphology has been detected by atomic force microscopy. A hillock structure is observed on the sample surface before and after annealing for 5-10 min. Surface blister formation is observed with an increasing annealing time. The variation of crystal damage with annealing time has been investigated by Rutherford backscattering/channeling. The intensity of the damage peak first increases with annealing time, reaches maximum at an annealing time of 60 min and then decreases. Helium-induced bubbles and residual defects have been observed by transmission electron microscopy, which shows that dislocations are close to the bubbles. (C) 2010 Elsevier B.V. All rights reserved.

The annealing behavior of Cu nanoparticles in Ar-ion implanted spinel

Magnesium aluminate spinel crystals (MgAl2O4 (1 1 0)) deposited with 30 nm Cu film on surface were implanted with 110 key Ar-ions to a fluence of 1.0 x 10(17) ions/cm(2) at 350 degrees C, and then annealed in vacuum condition at the temperature of 500, 600, 700, 800 and 900 degrees C for 1 h, respectively. Ultraviolet-visible spectrometry (UV-VIS), scanning electron microscopy (SEM), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) were adopted to analyze the specimens. After implantation, the appearance of surface plasmon resonance (SPR) absorbance peak in the UV-VIS spectrum indicated the formation of Cu nanoparticles, and the TEM results for 500 degrees C also confirmed the formation of Cu nanoparticles at near-surface region. In annealing process, The SPR absorbance intensity increased at 500 and 700 degrees C, decreased with a blue shift of the peak position at 600 and 800 degrees C, and the peak disappeared at 900 degrees C. The SPR absorbance intensity evolution with temperature was discussed combined with other measurement results (RBS, SEM and TEM). (C) 2010 Elsevier B.V. All rights reserved.

Structural and optical properties of 6H-SiC helium-implanted at 600 K

Single crystals of 6H-SiC were implanted at 600 K with 100 key He ions to three successively fluences and subsequently annealed at different temperatures ranging from 873 to 1473 K in vacuum. The recovery of lattice damage was investigated by different techniques including Rutherford backscattering spectrometry in channeling geometry, Raman spectroscopy and Fourier transform infrared spectroscopy. All three techniques showed that the damage induced by helium ion implantation in the lattice is closely related to the fluence. Rutherford backscattering spectrometry/channeling data on high temperature implantations suggest that for a fluence of 3 x 10(16) He+/cm(2), extended defects are created by thermal annealing to 1473 K. Apart from a well-known intensity decrease of scattering peaks in Raman spectroscopy it was found that the absorbance peak in Fourier transform infrared spectroscopy due to the stretching vibration of Si-C bond shifted to smaller wave numbers with increasing fluence, shifting back to larger wave numbers with increasing annealing temperature. These phenomena are attributed to different lattice damage behavior induced by the hot implantation process, in which simultaneous recovery was prevailing. (C) 2010 Elsevier B.V. All rights reserved.