电离辐射对Si_3N_4/SiO_2/Si双界面系统的作用

采用氩离子刻蚀XPS(X光激发电子能谱)分析对S i3N4/S iO2/S i双界面系统进行了电离辐照剖面分析。实验结果表明:电离辐照能将S iO2和S i构成的界面区中心向S i3N4/S iO2界面方向推移,同时S iO2/S i界面区亦被电离辐照展宽。在同样偏置电场中辐照,随着辐照剂量的增加电离辐照相当程度地减少位于S iO2/S i界面区S i3N4态(结合能B.E.101.8 eV)S i的浓度。同时辐照中所施偏置电场对S iO2/S i界面区S i3N4态键断开有显著作用。文中就实验现象的机制进行了初步探讨。     

不同退火氛围对TiN/HfO2/SiO2/Si结构电荷分布的影响

热退火技术是集成电路制造过程中用来改善材料性能的重要手段。系统分析了两种不同的退火条件(氨气氛围和氧气氛围)对TiN/HfO₂/SiO₂/Si结构中电荷分布的影响,给出了不同退火条件下SiO₂/Si和HfO₂/SiO₂界面的界面电荷密度、HfO₂的体电荷密度以及HfO₂/SiO₂界面的界面偶极子的数值。研究结果表明,在氨气和氧气氛围中退火会使HfO₂/SiO₂界面的界面电荷密度减小、界面偶极子增加,而SiO₂/Si界面的界面电荷密度几乎不受退火影响。最后研究了不同退火氛围对电容平带电压的影响,发现两种不同的退火条件都会导致TiN/HfO₂/SiO₂/Si电容结构平带电压的正向漂移,基于退火对其电荷分布的影响研究,此正向漂移主要来源于退火导致的HfO₂/SiO₂界面的界面偶极子的增加。     

在SiO_2中掺Al对Au/纳米(SiO_2/Si/SiO_2)/p-Si结构电致发光的影响

利用射频磁控溅射方法 ,制成纳米 Si O2 层厚度一定而纳米 Si层厚度不同的纳米 (Si O2 / Si/ Si O2 ) / p- Si结构和纳米 (Si O2 ∶ Al/ Si/ Si O2 ∶ Al) / p- Si结构 ,用磁控溅射制备纳米 Si O2 ∶ Al时所用的 Si O2 / Al复合靶中的 Al的面积百分比为 1% .上述两种结构中 Si层厚度均为 1— 3nm ,间隔为 0 .2 nm .为了对比研究 ,还制备了 Si层厚度为零的样品 .这两种结构在 90 0℃氮气下退火 30 m in,正面蒸半透明 Au膜 ,背面蒸 Al作欧姆接触后 ,都在正向偏置下观察到电致发光 (EL ) .在一定的正向偏置下 ,EL强度和峰位以及电流都随 Si层厚度的增加而     

在SiO2中掺Al对Au/纳米(SiO2/Si/SiO2)/p-Si 结构电致发光的影响

利用射频磁控溅射方法,制成纳米SiO2层厚度一定而纳米Si层厚度不同的纳米(SiO2/Si/SiO2)/p-Si结构和纳米(SiO2∶Al/Si/SiO2∶Al)/p-Si结构,用磁控溅射制备纳米SiO2∶Al时所用的SiO2/Al复合靶中的Al的面积百分比为1%．上述两种结构中Si层厚度均为1—3nm,间隔为0.2nm．为了对比研究,还制备了Si层厚度为零的样品．这两种结构在900℃氮气下退火30min,正面蒸半透明Au膜,背面蒸Al作欧姆接触后,都在正向偏置下观察到电致发光（EL）．在一定的正向偏置下,EL强度和峰位以及电流都随Si层厚度的增加而同步振荡,位相相同．但掺Al结构的发光强度普遍比不掺Al结构强．另外,这两种结构的EL具体振荡特性有明显不同．对这两种结构的电致发光的物理机制和SiO2中掺Al的作用进行了分析和讨论．     

Improved Interface and Electrical Properties by Inserting an Ultrathin SiO2 Buffer Layer in the Al2O3/Si Heterojunction

An ultrathin SiO₂ interfacial buffer layer is formed using the nitric acid oxidation of Si (NAOS) method to improve the interface and electrical properties of Al₂O₃/Si, and its effect on the leakage current and interfacial states is analyzed. The leakage current density of the Al₂O₃/Si sample (8.1 × 10^?9 A cm^?2) due to the formation of low‐density SiO_x layer during the atomic layer deposition (ALD) process, decreases by approximately two orders of magnitude when SiO₂ buffer layer is inserted using the NAOS method (1.1 × 10^?11 A cm^?2), and further decreases after post‐metallization annealing (PMA) (1.4 × 10^?12 A cm^?2). Based on these results, the influence of interfacial defect states is analyzed. The equilibrium density of defect sites (N_d) and fixed charge density (N_f) are both reduced after NAOS and then further decreased by PMA treatment. The interface state density (D_it) at 0.11 eV decreases about one order of magnitude from 2.5 × 10¹² to 7.3 × 10¹¹ atoms eV^?1 cm^?2 after NAOS, and to 3.0 × 10¹⁰ atoms eV^?1 cm^?2 after PMA. Consequently, it is demonstrated that the high defect density of the Al₂O₃/Si interface is drastically reduced by fabricating ultrathin high density SiO₂ buffer layer, and the insulating properties are improved.     

Growth of a Ge Layer on a Si/SiO2/Si(100) Structure by the Hot Wire Chemical Vapor Deposition

Semiconductors - Ge/Si layers are formed on Si/SiO2/Si(100) substrates and are investigated for different growth temperatures. The Si layer is grown by molecular-beam epitaxy, while the Ge layer is...     

金属保护层改善NiSi/Si肖特基势垒均匀性的研究

用溅射-退火反应的方法制作NiSi／Si肖特基二极管，采用Ti和Co两种金属保护层结构，以提高硅化物的形成质量。对肖特基二极管反向I-V特性的测量结果表明：相对于没有保护层的样品，有保护层样品的反向电流明显减小，而且Ti保护层结构比Co保护层结构的作用更明显；没有保护层的管子和有保护层的管子具有不同的边缘特性。实验数据能够很好地用非均匀肖特基势垒输运模型拟合。提取出的参数表明，保护层结构在不同程度上有效地提高了肖特基势全的均匀性，从而减小了肖特基二极管的反向电流；边缘特性的差异性也是由于肖特基势垒均匀性的改变而导致的。金属保护层能提高肖特基势全的均匀性是因为保护层抑制了工艺过程中的氧污染。     

具有SiO_2绝缘层的硅基聚酰亚胺电容式湿度传感器的特性研究

传统夹层聚酰亚胺电容式湿度传感器在亚胺化过程中感湿膜会因挥发物产生微孔,对这种传感器的成品率造成很大影响。为此,从元件的结构入手,制作Si-SiO2-PI结构的湿度传感器,对该种传感器的特性进行了测试,并与传统夹层式结构的样品进行了对比。研究表明,Si-SiO2-PI结构的湿度传感器在同等测试条件下,其电容值要比传统结构样品高25%,湿度灵敏度达到1.24 pF / %,具有重复性好和一致性高的优点,并且特别利于克服薄膜孔洞和厚度不均匀造成的短路现象,有利于批量生产。     

具有分布式并行I/O接口的分布式并行服务器系统的性能研究

分布式并行是多年来的一个研发热点,但其研发仅限于分布式并行系统的内部.服务器和外界(如客户机)的交互仅通过一条通道(如一台计算机)完成,这一瓶颈限制了系统可靠性/可用性,加速比与效率,系统频带和I/O响应速度等.本文提出的具有分布式并行I/O接口的分布式并行服务器使其中的各节点机均可直接与众多客户机交互作用,设计保证80%以上的客户请求均一次直接发往能提供服务的服务器中的节点机,仅有少量请求需要在节点间进行动态负载再调度.这是一种面向宽带的宽带网络服务器.本文的重点是将这种服务器与单机、镜像/双机热备份、群集服务器进行性能比较.结果表明,具有这种I/O接口的分布式并行服务器性能最佳.这种服务器的第一个版本已经研发成功,投入使用,并将进入市场.     

W阻挡层对Al/TiSi_2/Si接触系统热稳定性的影响

用X射线衍射及I—V测量技术研究了W在Al/TiSi_2/Si接触系统中的作用,并与不加W阻挡层的情况作了比较。热稳定性的研究表明:在高达100℃退火时,W阻挡层能够阻止Al与TiSi_2的完全反应。对Al/W/TiSi_2/Si接触二极管的I—V测试表明,在480℃以内退火,势垒高度变化不大。当退火温度达500℃时,Si通过TiSi_2层扩散至W阻挡层而使之失效.     

Tunneling in MOS Systems: The Dependence of the Effective Barrier Height on the Structure of the Transition Layer at the Si/SiO2Interface in the Presence of Impurities

Electron tunneling through a thin (2–5 nm) SiO₂layer in MOSFETs is studied theoretically. The relationship between the effective barrier height and the structure of the transition layer at the Si/SiO₂interface in the presence of impurities is investigated. The barrier height as a function of the normal coordinate is determined. The influence of sporadic traps is taken into account. The results incorporate experimental data, which were previously obtained.     

工艺参数对真空紫外光直接光CVD SiO2／Si界面特性的影响

采用高频（１ＭＨｚ）Ｃ－Ｖ测试和红外谱，研究了工艺参数对Ｘｅ激发真空紫外光（ＶＵＶ）直接光ＣＶＤ ＳｉＯ２的ＳｉＯ２／Ｓｉ界面特性的影响。结果表明：衬底温度Ｔｓ对固定氧化物电荷密度ΔＮｏｔ、慢界面态密度ΔＮｓｔ的影响比反应室总气压Ｐｃ和ＳｉＨ２／Ｏ２分压比显著。ΔＮｏｔ和ΔＮｓｔ在１１０℃附近有极小值，大小为１０＾１０ｃｍ＾－２量级。Ｔｓ〉１２０℃，ΔＮｏｔ呈正电荷性，Ｔｓ〈１１０℃，ΔＮｏｔ呈负     

Features of the stress-strain state of Si/SiO2/Ge heterostructures with germanium nanoislands of a limited density

Within the elastic continuum model, with the use of the finite-element method, the stress-strain state of silicon-germanium heterostructures with semispherical germanium islands grown on an oxidized silicon surface is calculated. It is shown that as the density of islands is increased to limiting values, in the SiGe structure with open quantum dots the value and spatial distribution of the elastic-strain fields significantly change. The results of theoretical calculation allow the heterostructure portions with the maximum variation in the stress-strain state to be determined. The position of such a portions can be controlled by changing the density of islands.     

零偏源MOS结构的栅电荷弛豫机制及近少子带边界面态分布的瞬态谱测定

讨论了小方栅脉冲下零偏置源MOS结构栅电荷弛豫的机制.证明了当费米能级接近少子带边时,引起栅电荷弛豫的起因将由界面态俘获发射电荷的过程变成受其延迟的表面少子扩散漂移过程.对后一过程进行理论分析导出的栅电荷公式与实验取得了一致.在此基础上提出了根据栅电荷波形参数确定栅电荷变化量中界面态贡献的大小,进而测定近少子带边一侧界面态密度的测量原理.获得了覆盖的能量范围一直延伸到距少子带边 0.05 eV处的界面态密度能量分布.在不同类型样品中获得了具有共同特征的结果.     

Hematite Photoanodes: Synergetic Enhancement of Light Harvesting and Charge Management by Sandwiched with Fe2TiO5/Fe2O3/Pt Structures

Efficient charge separation and transport as well as high light absorption are key factors that determine the efficiency of photoelectrochemical (PEC) water splitting devices. Here, a PEC device consisting of a hematite nanoporous film deposited on Pt nanopillars, followed by the decoration with an Fe₂TiO₅ passivation layer, is designed and fabricated. This structure can largely improve the light absorption in the composite materials, and significantly enhance the water oxidation performance of hematite photoanodes. The Fe₂TiO₅ thin shell and Pt underlayer significantly improve the interfacial charge transfer while minimizing the hole‐migration length in Fe₂O₃ photoanodes, leading to a drastically increased photocurrent density. Specially, the Fe₂TiO₅/Fe₂O₃/Pt photoanode yields an excellent photoresponse for PEC water splitting reactions with 1.0 and 2.4 mA cm^?2 obtained at 1.23 and 1.6 V_RHE under AM 1.5G illumination in 1 m KOH. The resulting photocurrents are 2.5 times enhanced compared to a pristine Fe₂O₃ photoanode of the same geometry. These results demonstrate a synergistic charge transfer effect of Fe₂TiO₅ and Pt layers on hematite for the improvement of PEC water oxidation.     

Pt层对Ni/Si(100)固相反应NiSi薄膜高温稳定性的增强效应

研究了顺次淀积在 Si (10 0 )衬底上的 Ni/ Pt和 Pt/ Ni的固相硅化反应 .研究发现 ,当 1nm Pt作为中间层或覆盖层加入 Ni/ Si体系中时 ,延缓了 Ni Si向 Ni Si2 的转变 ,相变温度提高 .对于这种双层薄膜体系 ,80 0℃退火后 ,XRD测试未检测到 Ni Si2 相存在 ;85 0℃退火后的薄膜仍有一些 Ni Si衍射峰存在 . 80 0℃退火后的薄膜呈现较低的电阻率 ,在 2 3— 2 5 μΩ· cm范围 .上述薄膜较 Ni/ Si直接反应生成膜的热稳定性提高了 10 0℃以上 .这有利于Ni Si薄膜材料在 Si基器件制造中的应用 .     

Pt层对Ni/Si(100)固相反应NiSi薄膜高温稳定性的增强效应

研究了顺次淀积在Si(100)衬底上的Ni/Pt和Pt/Ni的固相硅化反应．研究发现,当1nm Pt作为中间层或覆盖层加入Ni/Si体系中时,延缓了NiSi向NiSi2的转变,相变温度提高．对于这种双层薄膜体系,800℃退火后,XRD测试未检测到NiSi2相存在;850℃退火后的薄膜仍有一些NiSi衍射峰存在．800℃退火后的薄膜呈现较低的电阻率,在23—25μΩ*cm范围．上述薄膜较Ni/Si直接反应生成膜的热稳定性提高了100℃以上．这有利于NiSi薄膜材料在Si基器件制造中的应用．     

KFM detection of charges injected by AFM into a thin SiO2 layer containing Si nanocrystals

Charge retention of Si nanocrystals elaborated by ultra-low energy ion implantation and thermal annealings into a thin SiO₂ layer is characterized by atomic force microscopy (AFM) and Kelvin force microscopy (KFM). Electrons and holes are injected under ambient conditions by applying different bias to a conductive AFM tip in contact with the grounded sample. A surface potential mapping of the sample by KFM is continuously carried out after charge injection. The temporal decay of injected charges and their corresponding lateral spreading are quantified. The results show that the presence of Si nanocrystals leads to a strong charge confinement.     

Investigation into the Internal Electric-Field Strength in the Active Region of InGaN/GaN-Based LED Structures with Various Numbers of Quantum Wells by Electrotransmission Spectroscopy

Semiconductors - The internal electric fields of InGaN/GaN-based green-emission LED heterostructures with various numbers of quantum wells in the active region are investigated by...     

具有MgF2夹层有机—无机复合电致发光器件的性能

本文把MgF2引入有机电致发光器件的电子传输层和穴传传输层之间,制备了有机－无机复合的电致发光器件。通过发光和电学研究发现,MgF2层的引入可以明显抑制激基复合物的形成,增加短波长光的发射的强度;同时,它对降低起亮电压,改善器件发光性能具有明显的效果。