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

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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. ***