六硼化镧阴极

本文综述了紫红樱桃色六硼化镧粉末的制造过程以及间热式、直热式六硼化镧阴极的结构和性能.着重指出了利用冷压、热压等手段制造出几种六硼化镧阴极结构及其更复杂形状可能的途径.对工作过程中六硼化镧阴极表面出现正电性薄膜的两种不同论点,作了较详细的阐述.最后,还指出在六硼化镧阴极基金属的表面涂敷一层二硅化钼或经碳化处理,可防止硼原子向基金属内部扩散,能更进一步延长阴极的有效使用寿命.     

离子注入中硼在Rp缺陷的析出模型

建立了一种析出模型用来模拟硼在硅中的扩散现象,描述了硼原子与离子注入引起的R.缺陷之间的相互作用,解释了非活性硼峰形成的原因,与实验结果能够较好的吻合,为研究硼的扩散机理提供了很好的依据,为超浅结工艺模拟提供了基本模型,对于开发下一代集成电路研制的工艺模拟程序有着非常重要的意义.     

基于色心模型掺杂硼锗光纤材料紫外光诱导光敏特性的实验分析

本文研究和分析了制作光纤光栅锗硼硅材料的紫外光致折射率变化的规律,在不同脉冲和不同能流密度条件下,对载氢和未载氢两类锗硼硅光纤材料样品进行紫外漂白,然后测量它们紫外吸收变化光谱,通过色心模型Ｋ－Ｋ关系预言折射率变化量,并用色心模型理论对实施结果进行了分析讨论最后得出一些结论。     

硼对YBa2Cu3O7—δ陶瓷超导体超导性质的影响

制成组分为0≤x≤0.1的超导材料Y_(1-x)B_xBa_2Cu_3O_y.测量了从液氮温度到室温的该材料的电阻、磁化率和比热,并在室温下用X射线粉末衍射法分析了样品.结果表明掺硼减少了超导相的构成,引起部分非超导相.在硼浓度低时,没有迹象表明硼阳离子进入铜-氧面或铜-氧链.     

硼膜中的含氢量测量

硼膜中的含氢量多少对离子回旋共振加热的功率吸收和托卡马克放电过程中的氢的再循环行为均有很大的影响。实验证明，通过增加硼化过程中膜的生长速率及控制沉膜过程中的辉光放电状况，即可以有效地减少硼膜中的含氢量，使硼膜中的浓度控制在１０％以下，即Ｈ／Ｂ〈０．１。     

预非晶化硅中注入硼的异常扩散

预非晶化硅中,在非晶区和损伤区之间有一重损伤层存在,其边缘清楚,厚度约为20nm,包含有大量的扩展缺陷。它阻挡了尾部损伤区内簇团分解放出的硅间隙原子向非晶区扩散,大大削弱了非晶区内注入硼的异常扩散。选用条件适当的二次硅离子注入,使重损伤层加重加厚,从而完全阻止了非晶层内硼的异常扩散。本文在实验上为重损伤层阻止非晶区内硼异常扩散的模型提供证明。     

硼掺杂p-型半导体金刚石薄膜的气相合成及其掺杂行为的研究

利用灯丝热解CVD方法以甲烷和氢气为原料、以单质硼为掺杂源,制备了高晶体品质的硼掺杂多晶金刚石薄膜。其晶体结构及晶格常数与天然立方结构金刚石相同,硼掺杂后未引起金刚石薄膜中非金刚石碳含量的增加。证实了硼掺杂金刚石薄膜为p-型半导体材料,其最大硼掺杂浓度接近10~(20)cm~(-3),最大室温空穴载流子浓度达到10~(18)cm~(-3)。由硼掺杂金刚石薄膜红外吸收数据及类氢模型的估算证实了硼在金刚石的禁带中引入了位于价带以上约0.35eV的受主能级。     

美国科研人员称氢燃料电池技术取得突破

美国科研人员在最近出版的《美国化学学会杂志》上称,他们已研发出一种安全、有效提取和存储氢的方法,为推广使用氢燃料电池扫除障碍。负责研发这项技术的美国南加州大学助理教授特拉维斯-威廉姆斯在接受新华社记者电话采访时说:"我们已经找到一种提取和存储氢的化学方法。这种方法可以完成从硼烷氨中提取气态氢,再     

用二次离子质谱和扩展电阻探针技术测量硅中注入硼的深度分布及扩展电阻探针技术分辨率的估算

利用二次离子质谱和扩展电阻探针技术测量了硅中注入硼的深度分布.在适当的测量深度,用扩展电阻探针技术测得的结果对二次离子质谱技术测量的结果进行了标定,从而得到硅片中硼原子的深度分布.用近似模型估算了扩展电阻探针针尖半径对测试分辨率的影响.若探针针尖半径为r0,测量斜面的角度为ξ,在用扩展电阻探针技术测量载流子浓度的深度分布时,可以近似认为深度分辨率为7.86r0sinξ.还定性讨论了样品表面耗尽层对扩展电阻探针技术的影响.     

硼掺杂半导体金刚石薄膜的合成与红外吸收特性

用热丝协助化学气相沉积法，用Ｂ２Ｏ３作掺杂剂，用丙酮作碳源，成功地合成了硼掺杂半导体金刚石薄膜．本文报道了未掺杂和硼掺杂金刚石膜红外光谱的研究结果．实验结果表明：在０．３０８ｅＶ和０．３４１ｅＶ处产生的吸收是由于金刚石膜中硼原子的基态到第一、第二激发态的跃迁引起的．这个结果证实了硼原子在金刚石膜中以替位方式存在．     

First-principles study of metal atom adsorption on the boron-doped carbon nanotubes

Different boron-doped carbon nanotubes with dispersed Ni atoms as potential hydrogen storage materials are investigated using first-principles density functional theory. Our results show that substitution of neighboring two carbon atoms with boron atoms can improve the adsorption of Ni atom on the tube and fix the Ni atom around boron atoms, which prevent the aggregation of the Ni atoms on the surface. It is also found that this kind of boron-doped SWNT with Ni as catalyst has large hydrogen storage capacity.     

Increase of parasitic resistance in shallow p+ extensionby SiN sidewall process and its improvement by Ge preamorphization forsub-0.25-μm pMOSFET's

Anomalously high parasitic resistance is observed when SiN gate sidewall spacer is incorporated into sub-0.25-μm pMOSFET's. The parasitic resistance in p⁺ S/D extension region increases remarkably by decreasing BF₂ ion implantation energy to lower than 10 keV. It is confirmed that low activation efficiency of boron in p⁺ extension is the reason for such high parasitic resistance. The reduction of activation efficiency of boron may result from hydrogen passivation of boron acceptor; Fourier transform infrared absorption (FT-IR) measurement suggests that diffused hydrogen from SIN into p⁺ extension region forms the silicon-hydrogen-boron complex. It is also found that the activation efficiency of boron correlates well both with implantation energy of BF₂ and the amorphization rate of substrate. Therefore, in sub-0.25-μm era, the extra amorphization step is essential not only to form a shallow junction but also to enhance boron activation. Germanium preamorphization implantation (Ge PAI) is hence applied to p⁺ extension of 0.15 μm pMOSFET's. It is finally demonstrated that this Ge PAI process reduces the total parasitic resistance to improve the drain saturation current by up to 10%     

Electrical properties of the hydrogen defect in InP and the microscopic structure of the 2316 cm−1 hydrogen related line

We have studied the microscopic structure of a hydrogen related defect by measuringits vibrational IR absorption at 2315.6 cm⁻¹ in bulk InP crystals doped with deuterium. In contrast to the spectrum observed in nominally undoped samples (with only hydrogen present), the 2315.6 cm⁻¹ line in these samples containing both hydrogen and deuterium is split into at least three components approximately 0.5 cm⁻¹ apart. This can be explained if the defect contains more than one hydrogen atom; the additional lines are caused by mixed vibrational modes containing various combinations of hydrogen and deuterium. We present evidence that the formation of defect-hydrogen complexes leads to creation of a shallow intrinsic donor which can be annihilated under certain annealing conditions.     

The effect of silicon gate microstructure and gate oxide process onthreshold voltage instabilities in p+-gate p-channel MOSFETswith fluorine incorporation

Several phenomena have been identified which significantly reduce boron penetration for boron difluoride-implanted or boron/fluorine-co-implanted gates The fluorine-induced threshold-voltage (V_TP) shift is minimized by using an as-deposited amorphous silicon gate and a gate oxide process that excludes hydrogen chloride. The V_TP shift can be reduced to a level close to that of a boron-implanted gate, while maintaining the fluorine incorporation at the SiO₂/Si interface to lower interface-state density. A model based on the fluorine atom distribution is proposed to explain the observed V_TP shift     

三氯化硼红外多光子吸收分离硼同位素过程中氟氯化硼的生成

分析讨论了聚焦的TEACO_2激光辐照BCl_3-O_2体系分离硼同位素的反应产物和机制.BCl_3和O_2反应的稳定产物为B_2O_3,未发现(BOCl)_3.实验还表明,在强红外激光作用下,BCl_3与氟脂发生光化学反应.生成BFCl_2.讨论了多光子离解产物与氟脂反应的动力学过程,提出了可能的反应机制.     

The influence of rf induced bias on the properties of diamond-like carbon films prepared using ECR-CVD

The deposition of diamond-like carbon (DLC) films from a mixture of hydrogen and methane using the electron resonance chemical vapor deposition (ECR-CVD) method with radio-frequency (rf) bias is reported. The structural characteristics of the DLC films were characterized using Raman spectroscopy. The effects of the self-generated dc bias resulting from the rf power on the optical gap, Raman spectra, infrared (IR) absorption, and film hardness in depositions carried out at 7 and 15 mTorr process pressures were investigated. Under conditions of 100 W microwave power and for dc bias variation ranging from −10 to −200 V, there is evidence from Raman scattering analysis to show an increase in the DLC-like characteristic in films deposited at low dc bias at both process pressures. The variation of the D and G line peak position and intergrated intensity ratio (I_D/I_G) in the Raman spectra correlates well with the film hardness profile. There does not seem to be a relationship between the variation of the C-H absorption peak intensity in the IR spectra (bonded hydrogen content) and the optical gap, although films with the highest optical gap tend to show a relatively higher C-H absorption peak intensity in the IR spectra. Films deposited at high dc bias showed a reduction in the C-H infrared absorption, suggesting a reduction in the bonded hydrogen content.     

Isotopic effects in the infrared absorption spectra of electrically active impurities in silicon 28, 29, and 30 with high isotopic enrichment

The results of studying the IR absorption spectra of shallow donors and acceptors in high-purity stable ²⁸Si(99.99%), ²⁹Si(99.92%), and ³⁰Si(99.97%) isotope single crystals grown by the method of float zone melting were reported. The content of residual boron, phosphorus, and arsenic impurities in the studied single crystals was determined with a detection limit of 1 × 10¹², 4 × 10¹¹, and 1 × 10¹² at./cm³, respectively. The results of the IR spectroscopic estimation of the content of shallow donors and acceptors were in good agreement with the data obtained from the Hall effect measurements for the concentration of free charge carriers. The parameters of the absorption lines of boron and phosphorus impurities in the single crystal of silicon isotopes were studied. The change in the isotope composition of silicon was shown to lead to the shift of the energy spectrum of shallow impurity sites towards higher energies with an increase in the atomic weight of an isotope.     

多层a-Si∶H/a-SiNx∶H薄膜中氢含量的研究

将PECVD方法制备的多层a-Si∶H/a-SiN_x∶H膜在N_2气氛中进行不同温度的退火处理后,利用红外吸收谱、核反应方法,次级离子质谱(SIMS)和透射电镜(TEM)对膜中氢从表面渗出及其与温度的依赖关系进行了测试和分析。最后对氢的外扩散现象提出了几种可能的简单解释。     

硅中与钯相关的深能级的研究

本文采用多种硅材料,对扩Pd快速淬火在硅中引入的两个与Pd相关的新能级E_A(E_c-0.37eV)、E_B(E_c-0.59eV)进行了系统的实验研究,结果进一步支持了E_A和E_B属于同一缺陷的不同能量状态的看法,但发现缺陷的微观构成与B无直接关联,而很可能同间隙Pd与硅中本征空位缺陷形成的络合物相关.     

The electronic and optical properties of amorphous silica with hydrogen defects by ab initio calculations

Hydrogen can be trapped in the bulk materials in four forms:interstitial molecular H2,interstitial atom H,O-H+(2Si=O-H)+,Si-H-(4O-SiH)-to affect the electronic and optical properties of amorphous silica.Therefore,the electronic and optical properties of defect-free and hydrogen defects in amorphous silica were performed within the scheme of density functional theory.Initially,the negative charged states hydrogen defects introduced new defect level between the valence band top and conduction band bottom.However,the neutral and positive charged state hydrogen defects made both the valence band and conduction band transfer to the lower energy.Subsequently,the optical properties such as absorption spectra,conductivity and loss functions were analyzed.It is indicated that the negative hydrogen defects caused the absorption peak ranging from 0 to 2.0 eV while the positive states produced absorption peaks at lower energy and two strong absorption peaks arose at 6.9 and 9.0 eV.However,the neutral hydrogen defects just improved the intensity of absorption spectrum.This may give insights into understanding the mechanism of laser-induced damage for optical materials.