GOALI: Atomic Correlations in Disordered Materials Observed using Variable Coherence Transmission Electron Microscopy

该GOALI研究项目部分得到了MPS理事会多学科活动办公室（OMA）的支持，旨在开发一种利用透射电镜表征非晶和无序材料网络结构的定量技术。虽然TEM在晶体材料缺陷的研究上取得了很大的成功，但迄今为止在表征非晶材料方面还不太有用。目前的项目是基于这样一个前提，即高分辨率的透射电镜图像包含了大量关于无序材料微观结构的信息。所提出的新技术的一个重要方面，将在实验和理论上进行，是使用三体相关函数来提供对中程阶的新见解。探索直接从实验中提取高阶相关函数的理论方法。要研究的材料包括非晶半导体、栅极电介质和铁电体。这项工作将由两名PI合作进行，一名来自大学，一名来自工业实验室，另一名来自共同监督的研究生，该研究生将从大量接触工业研究中受益。这项GOALI研究项目得到了MPS理事会多学科活动办公室（OMA）的部分支持，将由一组材料科学家进行，他们都是使用透射电子显微镜（TEM）的专家，一位在研究型大学，另一位在领先的工业研究实验室。一名优秀的研究生将受益于两位PI的共同监督，并且在工业实验室进行论文研究的过程中，他/她将获得宝贵的经验和行业联系。该项目旨在扩展TEM在评估实际材料中存在的无序程度方面的有用性，包括半导体晶体管器件中核心的栅极氧化物。了解给定材料的无序程度对于预测其在给定应用中的性能是有用的。该项目的成果预计将包括有关TEM使用的新知识，以及对研究生进行大量工业接触的优秀培训经验。＊＊＊

w:\awards\awards96\num.doc 9703906 Gibson This GOALI research project, which is supported in part by the Office of Multidisciplinary Activities (OMA) of the MPS Directorate, intends to develop a quantitative technique using the TEM to characterize network structure in amorphous and disordered materials. Although TEM has been highly successful in the study of defects in crystalline materials, it has been less useful thus far in characterizing amorphous materials. The present project is based on the premise that the high resolution TEM image, nonetheless, contains a wealth of information about the microstructure in disordered materials. An important aspect of the proposed new technique, which will be pursued experimentally and theoretically, is the use of the three-body correlation function to give new insight into medium range order. Theoretical methods for extracting higher-order correlation functions directly from experiment will be explored. Materials to be studied include amorphous semiconductors, gate dielectrics, and ferroelectrics. This work will be carried out collaboratively by two PI's , one from a university, one from an industrial lab, and by a jointly supervised graduate student who will benefit from a significant exposure to industrial research. %%% This GOALI research project, which is supported in part by the Office of Multidisciplinary Activities (OMA) of the MPS Directorate, will be carried out by a team of materials scientists, both experts in use of the Transmission Electron Microscope (TEM), one at a research university, and the other at a leading industrial research laboratory. An excellent graduate student will benefit from joint supervision by the two PI's, and in the process of doing a significant portion of his/her thesis research at the industrial laboratory, will gain valuable experience and contacts in industry. The project is designed to extend the usefulness of the TEM in assessing the degree of disorder present in real materials, including gate oxides which are central in semiconductor transistor devices. Knowledge of the degree of disorder in a given material can be useful in predicting its performance in a given application. The outcomes of the project are expected to include new knowledge concerning the use of the TEM, and an excellent training experience with significant industrial exposure, for a graduate student. ***