低电阻率、大升阻比BaTiO_3基PTCR陶瓷材料

研究了Sb2O3和Ta2O5双施主掺杂对低电阻率的BaTiO3陶瓷PTC特性的影响。在Sb2O3和Ta2O5的摩尔分数分别为0.1%和0.01%时,得到了室温电阻率为4.59 Ω·cm,升阻比为3.4的优质PTCR陶瓷材料。通过XRD 、SEM显微结构分析;复阻抗测试,估计晶粒和晶界电阻值,探讨了Sb2O3和Ta2O5的作用机制。     

高性能BaTiO3基PTCR陶瓷的制备与研究

报道了在传统 Ba Ti O3基 PTCR陶瓷基料中间时加入一定配比的 Pb3O4 和 Ba CO3所产生的低阻现象。当 x=2 .5和 Pb/Ba=1.3时 ,陶瓷在 114 0°C保温 6 0 m in条件下获得了高性能的 PTCR瓷体 ,其室温电阻率与升阻比分别为 8Ω· cm和 4× 10 4 。结果表明 ,Pb3O4 和 Ba CO3的添加不仅能显著降低瓷体的室温电阻率 ,且还可以大幅度降低陶瓷的烧结温度。通过 XRD衍射谱分析并未在低阻瓷体中发现 Ba Pb O3相。根据所研究材料系统的一系列固态化学反应与缺陷反应提出了氧空位模型 ,并很好地解释了低阻化现象。     

双施主掺杂对BaTiO_3基PTC陶瓷性能的影响

研究了Nb2O5和Y2O3双施主一次掺杂对PTC BaTiO3陶瓷性能的影响。探讨了Nb2O5和Y2O3的作用机制,结果表明:Nb2O5主要是起施主作用;而Y2O3既可作为施主,又可起受主作用。添加适量的Y2O3,不仅可以降低电阻率,还可以提高升阻比。另外,还对改变施主掺杂顺序所产生的PTC效果进行了比较,发现施主二次掺杂的效果不如一次掺杂好。     

Ni/BaTiO3陶瓷复合材料的制备及其PTC效应

为获得低室温电阻率的PTC材料,以草酸为沉淀剂,采用液相包裹法制备了NiC2O4·2H2O/BaTiO3前躯体,并由其热分解制得Ni/BaTiO3基陶瓷复合材料。对该复合材料的研究表明,在还原气氛下烧成的Ni/BaTiO3基陶瓷复合材料具有很弱的PTC效应,但其PTC效应可通过适当的热处理工艺(600℃,空气气氛)得到有效恢复。其升阻比与室温电阻率为:(ρmax/ρmin=60)和(ρ=6.1?·cm)。     

稀土氯化物溶液掺杂BaTiO3基PTC陶瓷性能研究

采用稀土氯化物(YCl3、LaCl3)溶液作为施主掺杂剂,在1350℃空气气氛下烧结制备一系列BaTiO3陶瓷样品。借助XRD、XRF等手段,研究了氯化物溶液掺杂对BaTiO3基PTC陶瓷性能的影响。结果显示,YCl3掺杂样品的最低室温电阻率为17?·cm、LaCl3掺杂的为47?·cm,且样品都具有一定的PTC效应。室温电阻率大幅降低的原因,是引入的Cl元素有一部分能进入晶格取代O位起施主作用。     

硅射频微带电路S参数模拟研究

对不同电阻率硅片射频微带电路S参数进行了模拟研究。建立了 5层结构的微带电路物理结构模型 ,对两种电阻率硅片上不同尺寸 (2× 10 - 5m到 2 0× 10 - 5m)微带线 1～ 10GHz频率范围内的S1 1 和S2 1 参数进行模拟计算。研究结果表明 :减少低电阻率硅片 (3～ 8Ω·cm)线条宽度对减小信号反射和提高传输有益 ;高电阻率硅片 (130～ 15 0Ω·cm)上细线条尺寸微带电路信号反射和提高传输特性也更好。频率越高 ,高阻硅片微带电路的高频性能更好。     

多功能BaPbO_3陶瓷

<正> BaPbO_3陶瓷作为新型的多功能陶瓷已经引起人们的注意。其室温电阻率为5. 0×10~(-4)-8. 0×10~(-4)Ω·cm,可以作为导电陶瓷使用,并已经用作以Cr_2O_3为基的陶瓷湿度传感器电极。BaPbO_3陶瓷还具有高温PTC特性,居里温度可高达750℃左右,是一种高温PTC材料,可用于大功率     

ZnO-SnO_2透明导电膜的低温制备及性质

在室温下,采用射频磁控溅射法在70 5 9玻璃衬底上制备出Zn O- Sn O2 透明导电薄膜.制备的薄膜为非晶结构,并且薄膜的电阻率强烈地依赖于溅射气体中的氧分压.薄膜的最小电阻率为7.2 7×10 - 3Ω·cm,载流子浓度为4 .3e1 9cm- 3、霍尔迁移率为2 0 .5 cm2 / (V·s) ,在可见光范围内的平均透过率达到了90 % .     

液相施主及高钙添加对PTC材料性能的影响

采用液相施主掺杂和高钙添加相结合的方法,制得性能优良,适合程控电话交换机防雷击、防过流用的耐强电限流器件的PTC材料。在液相施主Y(NO3)3的添加量(摩尔分数)为0.4%,CaCO3添加量(摩尔分数)为15%时,得到了室温电阻率为140?·cm,居里点tC为74℃,阻温系数α为13.9%℃–1,升阻比lg(ρmax/ρmin)为7.2,耐压强度Vb≥260V/mm的PTC材料。     

PVT法掺钒SiC单晶生长电阻率变化规律研究

在采用COREMA方法测试SiC晶片电阻率时发现同一晶片电阻率相差较大,主要体现在高阻(>105Ω.cm量级)和低阻(<105量级)并存,有的甚至超高阻(>1012量级)和低阻并存,针对这一测试结果,开展了相关的实验研究,SiC单晶半绝缘性能的实现是通过在单晶生长过程中掺入深能级杂质V来补偿浅施主N和浅受主B,利用二次质谱(SIMS)对同一晶片不同区域的杂质元素V、N和B含量进行测试,结果发现晶片中V和N的含量都在1×1017量级时会出现同一晶片不同区域电阻率相差较大的情况,而当V含量在1×1017量级,N含量在5×1016量级以下时,可制备电阻率均匀性好的半绝缘SiC单晶。     

Silicon doping by nuclear transmutation

This paper describes, from the view of nuclear physics and radiochemistry, the mode of operation in doping semiconductor silicon with phosphorus by neutron irradiation. In addition to precise control of the irradiation fluence, this includes control of neutron-flux distribution, self-shielding and radioactive products from the silicon matrix and the surface impurities. The accuracy of the resistivity values achieved by this method is better than ± 5% at the predicated value. The good homogeneity of the dopant distribution is shown by the results of location-resolving resistivity measurements as well as by the breakdown radiation emitted by diodes. Neutron-bombarded homogeneously doped silicon (NBH-silicon) is used for routine manufacture of multi-diode vidicons and power devices.     

碲镉汞材料中Hg空位、Au、As掺杂的研究进展

碲镉汞材料是制造红外探测器的基础,高性能红外探测器对碲镉汞材料的要求越来越高。为了提升器件性能,必须提高碲镉汞材料的电学性能。而掺杂是一个很好的选择。碲镉汞材料掺杂可以分为n型和p型两种。对于n型掺杂来说,In是一种理想的掺杂剂,其掺杂研究目前已比较成熟。相对而言,p型掺杂研究还不是那么深入。Hg空位、Au、As掺杂均为碲镉汞材料中常见的p型掺杂手段。通过分析和总结近些年的部分相关文献,介绍了碲镉汞材料中Hg空位、Au、As掺杂的研究进展。     

InSb分子束外延原位掺杂技术研究

对InSb分子束外延薄膜的本征掺杂、N型掺杂以及P型掺杂进行了研究,其中分别以Be作P 型以及以Si、Te作N 型的掺杂剂。实验采用半绝缘的GaAs衬底作为InSb分子束外延用衬底,通过采用低温生长缓冲层技术降低大失配应力,获得高质量InSb外延膜。实验样品采用霍尔测试以及SIMS测试掺杂浓度和迁移率分析掺杂规律、掺杂元素偏聚和激活规律的影响因素。     

Doping of molecular beam epitaxy HgCdTe using an arsenic cracker source (As2)

This study investigated the incorporation of arsenic dimers (As₂), delivered from a “cracker” effusion cell. The HgCdTe epilayers were deposited under standard growth conditions. During deposition, arsenic was incorporated using both a standard arsenic effusion cell and a cracker cell. It was found that arsenic concentration rose dramatically as a function of cracker-zone temperature, particularly at temperatures above 600°C. This behavior was consistent with the temperature dependence of the effusion cell’s cracking efficiency, as determined by residual gas analysis. The temporal stability of the arsenic source was excellent. Arsenic concentrations of 2.8×10²⁰ cm⁻³ were achieved at a cracker temperature of 800°C. The arsenic beam-equivalent pressure, estimated from an uncorrected, nude ion-gauge reading, was ∼8×10⁻⁷ mbar.     

Vanadium doping of 4H SiC from a solid source: Photoluminescence investigation

Photoluminescence (PL) spectroscopy was used to monitor the efficiency of vanadium doping from a solid vanadium nitride source during CVD growth of 4H silicon carbide. More than an order of magnitude increase of vanadium related infrared photoluminescence in comparison to undoped samples was observed. By correcting the spectra for the contribution from the substrate, vanadium was shown to be incorporated in the epitaxial layer during CVD and was responsible for the observed differences in photoluminescence signal. Possible mechanisms of the vanadium transport to the growing layer and its incorporation are discussed.     

精密掺杂技术的发展与应用

微电子学和光电子学的迅速发展,要求能对掺入半导体晶片中的杂质数量、深度和浓度分布进行精密控制,因此原子平面掺杂和超浅层掺杂技术已成为发展新器件的重要工艺之一。本文介绍了当前三种主要的浅层或薄层平面掺杂技术的特点,并简要论述了它们在光电子器件和集成电路中的应用。     

Photochemical Doping and Tuning of the Work Function and Dirac Point in Graphene Using Photoacid and Photobase Generators

This work demonstrates that photochemical doping of CVD‐grown graphene can be easily achieved using photoacid (PAG) and photobase (PBG) generators such as triphenylsulfonium perfluoro‐1‐butanesufonate (TPS‐Nf) and 2‐nitrobenzyl N ‐cyclohexylcarbamate (NBC). The TPS‐Nf ionic onium salt photoacid generator does not noticeably dope or alter the electrical properties of graphene when coated onto the graphene surface, but is very effective at inducing p‐doping of graphene upon exposure of the PAG‐coated graphene sample. Likewise, the neutral NBC photobase generator does not significantly affect the electrical properties of graphene when coated, but upon exposure to ultraviolet light produces a free amine, which induces n‐doping of the graphene. Electrical measurements show that the doping concentration can be modulated by controlling the deep ultraviolet (DUV) light exposure dose delivered to the sample. The interaction between both dopants and graphene is also investigated. The photochemical doping process is able to tune the work function of the single‐layer graphene samples used in this work from 3.4 eV to 5.3 eV. Finally, a p–n junction is fabricated and analyzed, showing that it is possible to control the position of the two current minima (two Dirac points) in the ambipolar p–n junction.     

峰值掺杂结合线性掺杂对CNTFETs高频特性和开关特性影响

To overcome short-channel effects(SCEs) in high-performance device applications,a novel structure of CNTFET with a combination of halo and linear doping structure(HL-CNTFET) has been proposed.It has been theoretically investigated by a quantum kinetic model,which is based on two-dimensional non-equilibrium Green’s functions solved self-consistently with Poisson’s equations.We have studied the effect of halo doping and linear doping structure on static and dynamical performances of HL-CNTFET.It is demonstrated that a halo doping structure can decrease the drain leakage current and improve the on/off current ratio,and that linear doping can improve high-frequency and switching performance.     

掺镱双包层结构石英光纤的优化设计及制作

文章主要介绍了用MCVD工艺及溶液掺杂法制备掺Yb^3 双包层结构石英光纤的优化设计、原理及制作工艺，制作出Yb^3 掺杂浓度高(吸收损耗在976nm时为2～10dB／m)、本底损耗低(在1．3μm时为10dB／km)的掺Yb^3 双包层结构石英光纤。