基片温度对氧离子注入硅形成SOI材料的影响

系统地研究了氧离子注入时基片的温度对形成硅-绝缘体(SOI)材料的影响.研究结果表明:在氧离子注入时基片温度为550℃,注入能量为150 keV,注入剂量为1.8×1018ions/cm2的条件下,能够形成质量良好的SOI材料.     

氮气氛直拉硅的本征吸杂的研究

本文利用化学腐蚀、扩展电阻探针、透射电镜和电子探针等研究了氮气氛直拉硅的本征吸杂。经高——低——高三段热处理可获得比较完整的洁净区,体内有高密度且分布均匀的氧沉淀及其诱生缺陷,它们具有吸杂能力。洁净区内有片状残余缺陷。跟氩气氛直拉硅相比,氮气氛直拉硅的氧沉淀及其诱生缺陷有些不同。体内沉淀除片状外,主要是四面体。层错中央无氧沉淀。位错环是由氧沉淀诱生位错成为F—R源增殖的。     

一种克服SOI MOSFET器件自加热效应的方法

MOS器件的自加热效应将影响器件的性能．漏极电流将减小，长时间的可靠性也会受到影响．在SOI器件中，自加热甚至比埋葬式氧化物引起的问题更严重．本文通过在SOI和基片之间增加一条具有高导热和低导电的路径，减小了自加热的负面效应．     

Effect of Sequential Ions Implantation on Structure of Cu, Ag Nanoparticles

The preparation of metal nanoparticles composites by Cu, Ag ions sequential implantation is studied. The formation of Cu, Ag nanoparticles has been evidenced by grazing incidence X-ray diffraction, extended x-ray absorption fine structure and transmission electron microscopy. With the increase of Ag ion implantation dose, the size and density of Ag nanoparticles increase significantly.     

深亚微米NMOS/SOI热载流子效应及寿命预测

分析并模拟了SOINMOSFET的电源电压、工艺参数、沟道长度等对器件内部电场的影响，并对器件的低压热载流子效应进行实验测试，得到了不同应力条件下最大线性区跨导和阈值电压的退化结果，以及器件尺寸对这种退化的影响。并实验测试了一个SOINMOS器件电流电压特性的应力退化。     

SOI嵌入式DRAM技术动态钳制电位DTMOS器件性能的优化设计

描述了n-沟道动态电位DTMOS半导体器件的直流和高频特性，该器件制造采用了低功耗CMOS SOC工艺，同时也包含了高密度嵌入式DRAM技术．在本工作中的DTMOS器件在较早时候就发现性能优于本体接地(GB)和本体浮地(FB)的MOSFET器件．本器件具有无特性曲线缠绕、gm=936μS/μm,gout=36μS/μm,Ion/Ioff=210μA/0.1pA，在Vdd=1V时fmax=32GHz的良好特性。特别适用于低电压嵌入式基频电路并具有对射频RF前端电路的极佳性能，因此可以使嵌入式DRAM、数字电路、模拟电路和RF射频电路混合于一体，用在超低功耗、低成本的SOC(系统集成)芯片系统中．     

Hydrogen-induced cracking by nanovoids in 310 stainless steel

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Anticoagulation property and security of artificial heart valve material

Cardiovascular disease becomes one of the primary diseases that cause human death.Artificial heart valve’s replacement is the only way to save lives of the patients whoseheart valve is badly pathologically changed by rheumatic heart disease, retrogressiveheart disease, and bacterium caused endocarditis disease. The clinically used artificialheart valves are classified into biomedical heart valve and mechanical heart valve. Thebiocompatibility and anti-thrombus property of the biomedical heart…     

Effects of COOH~+ ion implantation on hemocompatibility of polypropylene

Carboxyl ion (COOH+) implantation was performed at 50 keV with different fluences for polypropylene. Hemocompatibility tests show that blood coagulation time and recalcification time of polypropylene were enhanced significantly with the increasing fluence. At the same time, the human endothelial cells grown on the surface of the implanted samples exhibited normal cellular growth and morphology. X-ray photoelectron spectroscopy and water contact angle analysis showed that COOH+ ion implantation rearranges chemical bonds and produces some new polar O-containing groups on the surface. The formation of polar functional groups, together with increase of roughness, induced an increase in hydrophilicity, which in turn improved the surface hemocompatibility of polypropylene.     

Property improvement of multilayer TiN/Ti films with C~+ implantation

Using the MEVVA ion source, carbon ions have been implanted in TiN coatings deposited by multi-arc ion plating The Vickers microhardness of the C+ -implanted TiN films increased with the increase in the ion flux and dose. X-ray diffraction (XRD) analysis showed that the TiC phases had been formed in the films. In addition, the films had the preferred growth orientations of TiN and TiC, both of which were (111) orientation after annealing at 500℃ for 30 min. Auger electron spectra analysis indicated that C+ -implanted profile was in typical Gaussian-like distribution in single films. The distribution with multipeaks of C atoms was obtained in multi-layer TiN/Ti. The possibility of the multilayer films (Ti (C, N)/TiN/Ti(C, N)/TiN and Ti(C, N)/TiC/Ti(C, N)/TiC) forming using the C-implanted TiN/Ti films is presented for the first time.     

硅中氧沉淀成核速率的测定

本文提出了硅中氧沉淀成核速率的测定方法并用该法测定了650—950℃温度区间的氧沉淀成核速率,为设计优化本征吸收工艺提供了可靠依据。     

Load Dependence of Nanohardness in Nitrogen Ion Implanted Ti6AI4V Alloy and Fractal Characterization

Three different nitrogen ion doses were implanted into a Ti6A14V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy （XPS）. Nano-indentation tests were carried out on the surface of the Ti6A14V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6A14V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6A14V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6A14V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.     

Load Dependence of Nanohardness in Nitrogen Ion Implanted Ti6Al4V Alloy and Fractal Characterization

Three different nitrogen ion doses were implanted into a Ti6Al4V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy (XPS). Nano-indentation tests were carried out on the surface of the Ti6Al4V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6Al4V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6Al4V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6Al4V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.     

Synthesis of Co-silicides and fabrication of microwave power device using MEVVA source implantation

Co synthesis silicides with good properties were prepared using MEVVA ion implantation with flux of 25-125μA/cm2 to does of 5×1017/cm2. The structure of the silicides was investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM analysis shows that if the ion dose is greater than 2×1017/cm2, a continuous silicide layer will be formed. The sheet resistance of Co silicide decreases with an increase in ion flux and ion dose. The formation of silicides with CoSi and CoSi2 are identified by XRD analysis. After annealing, the sheet resistance decreases further. A continuous silicide layer with a width of 90-133 nm is formed. The optimal implantation condition is that the ion flux and dose are 50μA/cm2 and 5×1017/cm2, respectively. The optimal annealing temperature and time are 900℃ and 10 s, respectively. The ohmic contact for power microwave transistors is fabricated using Co ion implantation technique for the first time. The emitter contact resistance and noise of the t     

The electrical conductivity characteristics of Fe/Cu nano-scale multilayer materials

A mathematical model for describing the relationship between electrical conductivity and the thickness of bilayer, ratio of sublayer thickness of a nano-scale multilayer material (MLM) is presented. Fe/Cu MLM was synthesized by electron beam physical vapor deposition (EB-PVD) technique, and the dependence of electrical conductivity of Fe/Cu MLM on the bilayer thickness and ratio of sublayer thickness were investigated. It is shown that the electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness decreases sharply when the thickness of bilayer becomes thinner than 30 nm. When the bilayer thickness is kept constant, the electrical conductivity linearly decreases with the increasing ratio of sublayer thickness. The values of parameters in the model were obtained by fitting the measured results of electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness. It is found that the calculated values agree well with measured ones.     

Nanometer structure and conductor mechanism of polymer modified by metal ion implantation

Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implantation with a dose ranging from 1 × 1016 to 2 × 1017 ions/cm2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been improved by metal ion implantation. The resistivity of implanted PET decreased obviously with an increase in ion dose. The results show that the conductive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to un-derstant the mechanism of electrical conduction, the structures of implanted layer were observed in detail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallic particles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 × 1017 ions/ cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 × 1017ions/ cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealed conducting mechanism evo     

纯铁及碳钢氮离子注入层结构和性能的研究

本文研究了纯铁,T_8钢、45~#钢氮离子注入层的结构和性能.结果表明,纯铁和T_8钢的显微硬度值均随氮离子注入剂量的提高而提高,纯铁和T_8钢中铁素体的点阵常数均随氮离子注入剂量的增大而增大.淬火马氏体组织的45~#钢的显微硬度则随氮离子注入剂量的增加而下降,并且有ε-F_(243)(C.N)化合物析出.离子注入使残余奥氏体发生了转变.     

Analysis of current waveform in plasma based ion implantation processes

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4H-SiC离子注入层的欧姆接触的制备

用氮离子注入的方法制备了4H-SiC欧姆接触层。注入层的离子浓度分布由蒙特卡罗分析软件TRIM模拟提取,Si面4H-SiC-Ni/Cr合金欧姆接触的特性由传输线方法结构进行了测量,得到氮离子注入层的方块电阻Rsh为30 kΩ/square,Ni/Cr合金与离子注入层的欧姆接触电阻ρc为7.1×10-4Ωcm2。     

铒离子注入晶体硅的射程分布和离散研究

用400 keV能量的铒离子垂直注入晶体硅(Si)样品中。利用卢瑟福背散射技术研究了能量为400 keV、剂量为5×1015ions/cm2的铒离子注入Si晶体的平均投影射程、射程离散和深度分布。测出的实验值和TRIM 98得到的理论模拟值进行了比较,发现实验值跟TRIM 98模拟计算的理论值符合较好。