RUI:CMMT:Multiscale Theory of Nano-Porous Electronic Materials: Case Study of Structure-leakage Relationships in Silicon Carbide Alloys

NON-TECHNICAL SUMMARY

This award supports theoretical and computational research and education aimed at understanding the electronic transport properties of nano-porous electronic materials, which are solid materials that have many tiny holes distributed throughout their interior so that their density is greatly reduced. Similar to the function of the air gap in a double paned window in improving its insulating properties, these pores improve the insulating properties of the material for electron transport. In this project, the PI and his team will develop a theory, valid across many orders of length scales, for investigating the electronic properties of nano-porous silicon carbide, a material which is being developed by the electronics industry as an insulator for high performance electronic devices, such as the processing chips used in laptops, cell phones and supercomputers. The goal is to determine the influence of impurities and microscopic defects naturally occurring in these systems on the macroscopic device operation. The approach will be to use very accurate quantum mechanical methods to study defects in small model systems and to develop larger models, based on information from these small model calculations, to predict the electronic transport properties of actual devices. The team will work in close collaboration with leading experimentalists to allow a feedback loop between theory and experiment.

This project will involve educating undergraduate and graduate students through research and related activities. Two undergraduates will visit research institutions to be trained by scientists from collaborating groups. Research results will be presented at meetings and work will be shared with industry representatives. The results from this project will be placed in context of related work and presented in a day-long workshop accessible to a wide audience including high school teachers, college students and faculty.

TECHNICAL SUMMARY

This award supports theoretical and computational research and education aimed at understanding the microstructural point defects that cause leakage in hydrogenated amorphous silicon carbide (a-SiC) alloys, which are important materials employed in nano-electronics and electro-mechanics applications. Specifically, in highly integrated circuits, such alloys serve as a back-end-of-the-line dielectric material. The PI and his team will use state-of-the-art density functional calculations and other computational methods in combination with experimental data to elucidate the properties of defects in device quality samples.

Based on recent experimental studies that have led to a wealth of new information on leakage currents in devices incorporating hydrogenated a-SiC, new microscopic models will be developed to match the range of experimental densities. Monte Carlo modeling methods will be used to explore the variable chemical arrangements found experimentally. Using the new microscopic models, the PI and his team will explore candidate point defects, characterize their properties, and find a match to the experimental leakage data. The results of the defect calculations will be incorporated into macroscopic leakage models with length scales matching the experimental systems and help in the development of a density of states thermodynamic model for hydrogen bonding in hydrogenated a-SiC. The computational work will be performed in close collaboration with leading experimentalists to allow a feedback loop between theory and experiment. The results will be valuable for developing new low-density hydrogenated a-SiC for nano-electronics applications, and for designing new amorphous nanomaterials.

This project will involve educating undergraduate and graduate students through research and related activities. Two undergraduates will visit research institutions to be trained by scientists from collaborating groups. Research results will be presented at meetings and work will be shared with industry representatives. The results from this project will be placed in context of related work and presented in a day-long workshop accessible to a wide audience including high school teachers, college students and faculty.