In-situ Transmission Electron Microscopy Studies of Metal Contact with InGaAs Nanochannels: Correlating Interface Reactions with Properties

非技术描述：该研究项目的重点是发展对纳米级金属-半导体反应的基本理解和控制。该研究小组利用透射电子显微镜（TEM）在原子尺度和真实的时间内研究这些纳米材料的结构、性能和功能之间的关系，这些纳米材料类似于一类新的纳米晶体管的工作条件。该研究有望为金属-半导体界面及其反应的基础材料科学提供新的见解，这是开发先进III-V族化合物半导体晶体管沟道金属接触的重要技术领域。外展和教育活动与研究活动很好地结合在一起，包括（1）在半导体异质结构和微制造的多学科领域开发当前研究生和本科生课程的新部分，以及（2）通过在加州大学圣地亚哥分校的各种外展活动，让高中和本科生参与动手研究，技术描述：在这个研究项目中，PI和他的团队利用一种新型的透射电子显微镜（TEM）测量方法来现场监测金属与III-V族半导体接触的反应。使用Ni硅化将III-V族半导体的鳍片晶片键合到Si TEM网格以形成独立的纳米级异质结构（即，纳米通道）用于原位加热研究和非原位电测量。多个纳米通道设计与不同的通道宽度，III-V晶体取向，和表面形态，可以集成在同一个TEM网格的组合原位和非原位研究。凭借这种能力，该团队将所产生的纳米通道成分，界面结构和晶体管性能与III-V鳍尺寸，晶体学取向和应力的影响相关联。特别是，这项研究工作允许对Ni和InGaAs之间的合金形成进行实验，作为尺寸和晶体取向的函数，并解决了以下科学问题：（i）III-V鳍尺寸对所形成的NiInGaAs合金的结构和组成的影响，（ii）界面和应变工程对超短沟道中的Ni-InGaAs反应和成核的影响，以及（iii）在多层接触叠层中有限的Ni扩散源对合金组成和结构的影响。这些发现对于开发用于亚10纳米III-V族化合物半导体晶体管沟道的欧姆接触具有重要意义。TEM网格上的纳米通道结构的晶片键合用于组合的原位TEM和非原位电研究可以潜在地使其他材料系统中的基本界面研究成为可能。

Non-Technical Description: This research project focuses on the development of fundamental understanding and control of metal-semiconductor reactions at nanoscale. The research team utilizes transmission electron microscopy (TEM) to study, at the atomic scale and in real time, the relationship between structure, properties, and functionality of these nanoscale materials similar to the working conditions of a new class of nanoscale transistors. The research is expected to provide new insights into the fundamental materials science on the metal-semiconductor interface and their reactions, an area of technological importance for developing metal contacts for advanced III-V compound semiconductor transistor channels. The outreach and educational activities are well integrated with the research activities and include (1) developing new sections in current graduate and undergraduate courses in the multidisciplinary area of semiconductor heterostructures and microfabrication, and (2) involving high-school and undergraduate students in hands-on research through various outreach activities at UC San Diego, with a particular emphasis on the inclusion of underrepresented groups.Technical Description: In this research project, the PI and his team utilize a novel transmission electron microscopy (TEM) measurement method to monitor, in-situ, reactions of metal contact with III-V semiconductors. Fins of III-V semiconductors are wafer bonded to a Si TEM grid using Ni silicidation to form free-standing nanoscale heterostructures (i.e., nanochannels) for both in-situ heating study and ex-situ electrical measurements. Multiple nanochannels designed with various channel widths, III-V crystallographic orientations, and surface morphologies, can be integrated on the same TEM grid for the combined in-situ and ex-situ studies. With this capability, the team correlates the resulted nanochannel composition, interface structure and the transistor performance with the effects of III-V fin size, crystallographic orientation and stress. In particular, the research work allows experiments on alloy formation between Ni and InGaAs as a function of size and crystal orientation and addresses the following scientific questions: (i) the III-V fin size effects on the structure and composition of the formed NiInGaAs alloys, (ii) the influence of interfaces and strain engineering on the Ni-InGaAs reaction and nucleation in ultra-short channels, and (iii) the effect of a limited Ni diffusion source in a multi-layered contact stack on the alloy composition and structure. The findings are important for developing Ohmic contacts for sub-10 nanometer III-V compound semiconductor transistor channels. The wafer bonding of nanochannel structures on TEM grid for the combined in-situ TEM and ex-situ electrical study can potentially enable fundamental interface studies in other materials systems.