High-aspect-ratio sub-micron trench etching on SOI using wet metal-assisted chemical etching (MaCE) process

摘要

This paper reports the first successful fabrication of a silicon (Si) MEMS resonator defined by submicron, high aspect-ratio vertical trenches using a fast `wet' Si etching method, named metal-assisted chemical etching (MaCE). Submicron vertical trenches with aspect ratio of 16:1 were etched by MaCE in a wet bath with assistance of gold thin film (Au) as a moving etching catalyst on a silicon-on-insulator (SOI) substrate. The etching was completed in only 10 minutes at room temperature. The sidewall of the trenches possesses roughness below 20 nm without scalloping features. These promising results of the first Si MEMS resonators fabricated by MaCE could pave the way for manufacturing of MEMS and NEMS devices using a simple, fast and low cost process compared to Deep Reactive-Ion Etching (DRIE).