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

非技术描述：本研究项目的重点是在纳米尺度上发展对金属-半导体反应的基本理解和控制。研究小组利用透射电子显微镜（TEM）在原子尺度上实时研究这些纳米级材料的结构、性质和功能之间的关系，这些纳米级材料类似于新型纳米级晶体管的工作条件。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，这对于开发先进III-V化合物半导体晶体管通道的金属接触具有重要的技术意义。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)通过加州大学圣地亚哥分校的各种外展活动，让高中生和本科生参与动手研究，特别强调包括代表性不足的群体。技术描述：在这个研究项目中，PI和他的团队利用一种新的透射电子显微镜（TEM）测量方法来现场监测金属与III-V半导体接触的反应。III-V型半导体的鳍片通过Ni硅化与Si TEM栅格结合，形成独立的纳米异质结构（即纳米通道），用于原位加热研究和非原位电测量。具有不同通道宽度、III-V型晶体取向和表面形貌的多个纳米通道可以集成在同一个TEM网格上进行原位和非原位联合研究。有了这种能力，该团队将所得到的纳米通道组成、界面结构和晶体管性能与III-V翅片尺寸、晶体取向和应力的影响联系起来。特别是，该研究工作允许Ni和InGaAs之间的合金形成实验作为尺寸和晶体取向的函数，并解决以下科学问题：(i) iii - v翅片尺寸对形成的NiInGaAs合金的结构和组成的影响，（ii）界面和应变工程对Ni- ingaas反应和超短通道成核的影响，以及（iii）多层接触堆中有限Ni扩散源对合金组成和组织的影响。研究结果对开发亚-10纳米III-V复合半导体晶体管通道的欧姆触点具有重要意义。纳米通道结构在透射电镜网格上的晶圆键合，为原位和非原位电研究提供了可能，为其他材料系统的基本界面研究提供了可能。

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.