METHOD OF ACHIEVING ATOMICALLY SMOOTH SIDEWALLS IN DEEP TRENCHES, AND HIGH ASPECT RATIO SILICON STRUCTURE CONTAINING ATOMICALLY SMOOTH SIDEWALLS

摘要

A high aspect ratio silicon structure comprises a silicon substrate (110) having a surface (111), an electrically insulating layer (120) over portions of the silicon substrate, a hardmask (130) over the electrically insulating layer, and a deep silicon trench (140) formed in the substrate. The deep silicon trench comprises a floor (141) and sidewalls (142) extending away from the floor, and the sidewalls are atomically smooth. In an embodiment, the atomically smooth sidewalls are achieved by providing a substrate having the deep silicon trench formed therein, forming a layer of water over the substrate and within the deep silicon trench, and exposing the substrate to a hydrogen fluoride vapor and to an ozone gas.