Filling high aspect-ratio nano-structures by atomic layer deposition and its applications in nano-optic devices and integrations

Abstract

Atomic layer deposition, a highly uniform and conformal deposition process, was utilized to fill trenches of various high aspect-ratio nano-grating structures. Dielectric (e.g., SiO2), metal (e.g., aluminum), and dielectric/metal (e.g., Au∕SiO2) hybrid nano-gratings with a linewidth down to <50nm and an aspect ratio up to 14:1 (700nm:50nm) were trench-filled with various materials particularly nano-laminate materials such as TiO2∕SiO2 and SiO2∕Al2O3. Various high-performance optical devices such as true-zero-order optical retarders (i.e., wave plates) and nanowire-grid polarizers were realized based on an UV-nanoimprint lithography process and the atomic layer deposition for trench fillings. Thanks to both unique material properties and nano-structure trench filling capability, the atomic layer deposition opens a path for innovative nano-structure based optical devices and integrated optical devices.