Appraising the extensibility of optics-based metrology for emerging materials
Bryan M. Barnes, Mark-Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
To advance computational capabilities beyond conventional scaling limitations, novel device architectures enabled by emerging materials may be required. Optics-based methodologies, central to modern-day process control, will be pursued by the nanoelectronics industry to interrogate these devices as optics are inexpensive, non-destructive, and fast. As geometrical and material complexity define new metrology requirements, these should be considered relative to the broader challenge of perpetuating optical methods for deep-subwavelength features. Using examples from our group and from others, the tailoring of the illumination conditions, sample, collection path, and data analysis are emphasized for model-based quantitative measurements. The successful fitting of structures comprised from these emerging materials will require the accurate determination of material optical constants, which may be both thickness dependent and anisotropic. Atomistic models such as tight-binding calculations or density-functional theory are potential approaches for understanding the dielectric function of these materials.