Characterization of advanced gate stacks for SiCMOS by electron energy-loss spectroscopy in scanning transmission electron microscopy
Characterization of advanced gate stacks for SiCMOS by electron energy-loss spectroscopy in scanning transmission electron microscopy
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DOI：
10.1016/j.elspec.2004.03.013
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发表时间：
2005-05-01
影响因子：
1.9
通讯作者：
Stemmer, S
中科院分区：
文献类型：
--
作者：
Foran, B;Barnett, J;Stemmer, S
由于SiO2栅极电介质和多晶Si栅极电极达到缩放极限，目前正在开发用于未来几代Si基场效应晶体管的新型金属氧化物膜和新型金属栅极。这些栅极叠层通常由亚纳米层组成。器件特性越来越多地受到层之间界面的复杂结构和化学性质的控制。扫描透射电子显微镜（STEM）中的电子能量损失谱（EELS）能够以任何其他技术无法比拟的空间分辨率提供对界面化学和局部原子结构的洞察。使用栅极堆叠与Hf-硅酸盐陶瓷作为例子，我们展示了STEM/EELS分析新型栅极堆叠的界面化学的能力。我们表明，先验未知的反应层的几个A的厚度可以被检测和识别，即使在存在大量的界面粗糙度，可能会掩盖这样的层在高分辨率图像。我们讨论了一些实验方面的STEM/EELS化学分析应用于栅极堆栈和影响的因素的解释。特别是，界面粗糙度的影响，光束传播，元素分析在一个严重的散射矩阵，和解释的EELS核心损失精细结构从多层膜进行了讨论。(c)2004 Elsevier B. V.保留所有权利。
Novel metal oxide films and new metal gates are currently being developed for future generations of Si based field-effect transistors as the SiO2 gate dielectric and polycrystalline Si gate electrode are reaching scaling limits. These gate stacks are often comprised of sub-nanometer layers. Device properties are increasingly controlled by the complex structure and chemistry of interfaces between the layers. Electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM) is capable of providing insights into interfacial chemistry and local atomic structure with a spatial resolution unmatched by any other technique. Using gate stacks with Hf-silicate dielectrics as examples, we demonstrate the capabilities of STEM/EELS for analyzing the interfacial chemistry of novel gate stacks. We show that a priori unknown reaction layers of a few A thickness can be detected and identified even in the presence of substantial interfacial roughness that may obscure such layers in a high-resolution image. We discuss some experimental aspects of STEM/EELS chemical profiling applied to gate stacks and the factors affecting the interpretation. In particular, the effects of interfacial roughness, beam spreading, elemental analysis in a heavily scattering matrix, and the interpretation of the EELS core-loss fine-structures from ultrathin layers are discussed. (c) 2004 Elsevier B.V. All rights reserved.