Pt redistribution in N-MOS transistors during Ni salicide process

Atom probe tomography was used to study the redistribution of platinum during Ni(10 at.%Pt) silicidation of n-doped polycrystalline Si. These measurements were performed after the two annealing steps of standard salicide process both on a field-effect transistor and on unpatterned region submitted to the same process. Very similar results are obtained in unpatterned region and in transistor gate contact. The first phase to form is not the expected δ-Ni2Si but the non stoichiometric θ-Ni2Si. Pt redistribution is strongly influenced by this phase and the final distribution is different from what is reported in literature. © 2013 Elsevier B.V. All rights reserved.

Ni(Pt)-silicide contacts on CMOS devices: Impact of substrate nature and Pt concentration on the phase formation

Ni silicides used as contacts in source/drain and gate of advanced CMOS devices were analyzed by atom probe tomography (APT) at atomic scale. These measurements were performed on 45 nm nMOS after standard self-aligned silicide (salicide) process using Ni(5 at.% Pt) alloy. After the first annealing (RTA1), δ-Ni2Si was the only phase formed on gate and source/drain while, after the second annealing (RTA2), two different Ni silicides have been formed: NiSi on the gate and δ-Ni2Si on the source and drain. This difference between source/drain and gate regions in nMOS devices has been related to the Si substrate nature (poly or mono-crystalline) and to the size of the contact. In fact, NiSi seems to have difficulties to nucleate in the narrow source/drain contact on mono-crystalline Si. The results have been compared to analysis performed on 28 nm nMOS where the Pt concentration is higher (10 at.% Pt). In this case, θ-Ni2Si is the first phase to form after RTA1 and NiSi is then formed at the same time on source (or drain) and gate after RTA2. The absence of the formation of NiSi from δ-Ni 2Si/Si(1 0 0) interface compared to θ-Ni2Si/Si(1 0 0) interface could be related to the difference of the interface energies. The redistributions of As and Pt in different silicides and interfaces were measured and discussed. In particular, it has been evidenced that Pt redistributions obtained on both 45 and 28 nm MOS transistors correspond to respective Pt distributions measured on blanket wafers. © 2013 Elsevier B.V. All rights reserved.

Direct epitaxial growth of θ-Ni2Si by reaction of a thin Ni(10 at.% Pt) film with Si(1 0 0) substrate

The reaction between an 11 nm Ni(10 at.% Pt) film on a Si substrate has been examined by in situ X-ray diffraction (XRD), atom probe tomography (APT) and transmission electron microscopy (TEM). In situ XRD experiments show the unusual formation of a phase without an XRD peak through consumption of the metal. According to APT, this phase has an Si concentration gradient in accordance with the θ-Ni2Si metastable phase. TEM analysis confirms the direct formation of θ-Ni2Si in epitaxy on Si(1 0 0) with two variants of the epitaxial relationship. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

硅化物表面与硅化物/硅界面研究——FeSi表面氧吸附与（Cr,pt）硅化物/硅界面研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Localized-Surface-Plasmon Enhanced the 357 nm Forward Emission from ZnMgO Films Capped by Pt Nanoparticles

The Pt nanoparticles (NPs), which posses the wider tunable localized-surface-plasmon (LSP) energy varying from deep ultraviolet to visible region depending on their morphology, were prepared by annealing Pt thin films with different initial mass-thicknesses. A sixfold enhancement of the 357 nm forward emission of ZnMgO was observed after capping with Pt NPs, which is due to the resonance coupling between the LSP of Pt NPs and the band-gap emission of ZnMgO. The other factors affecting the ultraviolet emission of ZnMgO, such as emission from Pt itself and light multi-scattering at the interface, were also discussed. These results indicate that Pt NPs can be used to enhance the ultraviolet emission through the LSP coupling for various wide band-gap semiconductors.

Thermal annealing behaviour of Pt on n-GaN Schottky contacts

The structural evolution and temperature dependence of the Schottky barrier heights of Pt contacts on n-GaN epilayer at various annealing temperatures were investigated extensively by Rutherford backscattering spectrometry, x-ray diffraction measurements, Auger electron spectroscopy, scanning electron microscopy and current-voltage measurements. The temperature dependence of the Schottky barrier heights may be attributed to changes of surface morphology of Pt films on the surface and variation of nonstoichiometric defects at the interface vicinity. Experimental results indicated the degradation of Pt contacts on n-GaN above 600 degreesC.

Characterization of deep levels in Pt-GaN Schottky diodes deposited on intermediate-temperature buffer layers

Gallium nitride (GaN)-based Schottky junctions were fabricated by RF-plasma-assisted molecular beam epitaxy (MBE). The GaN epitaxial layers were deposited on novel double buffer layers that consist of a conventional low-temperature buffer layer (LTBL) grown at 500 degreesC and an intermediate-temperature buffer layer (ITBL) deposited at 690 degreesC. Low-frequency excess noise and deep level transient Fourier spectroscopy (DLTFS) were measured from the devices. The results demonstrate a significant reduction in the density of deep levels in the devices fabricated with the GaN films grown with an ITBL. Compared to the control sample, which was grown with just a conventional LTBL, a three-order-of-magnitude reduction in the deep levels 0.4 eV below the conduction band minimum (Ec) is observed in the bulk of the thin films using DLTFS measurements.

Hydrogen sensors based on Pt-AlGaN/GaN back-to-back Schottky diode

In this paper, platinum (Pt) with a thickness of 45 nm was sputtered on the surface of AlGaN/GaN heterostructure to form the Schottky contact and the back-to-back Schottky diodes were characterized for H-2 sensing at room temperature. Both the forward and reverse current of the devices increased with exposure to H-2 gas, which was attributed to Schottky barrier height reduction caused by hydrogen absorption in the catalytic metals. A shift of 0.7 V at 297 K was obtained at a fixed forward current of 0.1 mA after switching from N-2 to 40% H-2 in N-2. The sensor's responses under different concentrations from 2500 ppm H-2 to 40% H-2 in N-2 at 297 K were investigated. Time response of the sensor at a fixed bias of 1 V was given. Finally, the decrease of the Schottky barrier height and the sensitivity of the sensor were calculated. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrogen sensors based on Pt-AlGN/AIN/GaN Schottky diode - art. no. 68291R

Pt/AlGaN/AlN/GaN Schottky diodes have been fabricated and characterized for H-2 sensing. Platinum (Pt) with a thickness of 20nm was evaporated on the sample to form the Schottky contact. The ohmic contact, formed by evaporated Ti/Al/Ni/Au metals, was subsequently annealed by a rapid thermal treatment at 860 degrees C for 30 s in N-2 ambience. Both the forward and reverse current of the device increased greatly when exposed to H-2 gas. The sensor's responses under different hydrogen concentrations from 500ppm to 10% H-2 in N-2 at 300K were investigated. A shift of 0.45V at 297K is obtained at a fixed forward current for switching from N-2 to 10% H-2 in N-2. Time response of the sensor at a fixed bias of 0.5 V was also measured. The turn-on response of the device was rapid, while the recovery of the sensor at N-2 atmosphere was rather slow. But it recovered quickly when the device was exposed to the air. The decrease in the barrier height of the diode was calculated to be about 160meV upon introduction of 10% H-2 into the ambient. The sensitivity of the sensor is also calculated. Some thermodynamics analyses have been done according to the Langmuir isotherm equation.

CFCs和PT方程

CFCs问题引来了广泛的研究.本文概述了CFCs问题.对于状态方程，讨论了1982年发表的PT方程。由此进一步比较讨论了RKS 和PR方程，另外总结了立方型方程的通式.这些对CFCs新工质的模拟计算都具有现实价值.

全固态电流型氧传感器及Pt-Fe复合催化剂的研究

控制电位电解型即电流型气体传感器由于具有检测气体种类多、浓度范围宽、体积小、价格低、测量精度高、可用于现场直接检测等优点，在环境监测与安全生产等领域中得到了广泛应用。本文论述了纳米级铂、碳纳米管负载铂及铂铁催化剂的合成方法，并对其进行了物理化学表征和电化学研究，主要结果如下： 采用柠檬酸钠还原的方法，合成了纳米级铂催化剂。TEM和XRD测试表明，该球形多晶铂的粒径为2－5nm。用此种铂催化剂制备了离子交换膜电极复合体，并组装了全固态电流型氧传感器；在对低浓度氧气进行测试时，具有高的灵敏度、较短的响应时间、较低的底电流和噪声，且响应信号与氧气的浓度呈良好的线性关系。 1．利用空气氧化和硝酸相结合对多壁碳纳米管进行了纯化，并利用1:1的H2SO4-HNO3混酸使其表面羧基化，TEM和CV测试表明多壁碳纳米管达到了纯化和表面官能团化的目的。 2．利用喷雾冷却法制备了多壁碳纳米管负载的铂及铂铁合金纳米级催化剂复合体，并利用TEM、EDS、XRD、ICP等进行了表征；在循环伏安扫描中，铂铁合金催化剂呈现较高的比表面积。将多壁碳纳米管负载的铂及铂铁合金纳米级催化剂应用于C1有机小分子的电化学氧化研究中发现，铂铁合金催化剂具有较高的催化活性.

贵金属（Au, Ag, Pt, Pd）纳米材料的可控合成及性能研究

功能化的贵金属纳米材料的设计和可控制备在材料科学研究领域引起了人们广泛的关注。贵金属纳米材料的光学、电学、磁学和催化等物理和化学性质不但与其大小有关，而且还与其形貌息息相关。因此寻求简单而有效的低温溶液合成途径以实现对贵金属纳米材料的尺寸和形貌控制尤为重要。本论文的主要研究内容可以归纳如下： (1)在水溶液中利用种子生长方法分别制备了核壳Au-Pd/Pt三金属复合纳米粒子和三层的核壳AuAg复合纳米粒子。这些纳米粒子的尺寸和组成可以通过改变金种子的加入量来加以调控。 (2)通过种子生长和取代沉积相结合的方法制备了具有金核铂/银双金属壳的铃铛状纳米粒子。通过扫描电子显微镜、透射电子显微镜和X-射线光电子能谱对所得纳米粒子的尺寸、结构和组成进行了表征。 (3)以二肽甘氨酰甘氨酸作为模板合成了具有[111]取向的单晶银纳米片。通过改变实验条件探讨了片状银纳米结构的形成机理。片状银纳米结构的产率可达到80%，反应物之间的摩尔比对产物的尺寸和形貌有至关重要的作用。 (4)将K3[Fe(CN)6]和Na2S2O3的混合溶液进行水热处理，得到了具有立方体形貌的FeIIIFeIII(CN)6（柏林绿）微晶。实验结果显示K3[Fe(CN)6]和Na2S2O3的摩尔比及其浓度对所得产物的尺寸、形貌和组成有决定性的作用。 (5)在室温下通过混合3, 3', 5, 5'-四甲基联苯胺和氯铂酸，成功合成了有机-无机杂化的纳米纤维。纳米纤维的尺寸和形状可以通过改变反应物的比和浓度加以控制。基于不同的实验结果，提出了纳米纤维的可能形成机理。