학술논문
High-Aspect-Ratio Thin-Film Stiffening Structures Made of Atomic-Layer-Deposited Alumina and Its Application to a Scanning Micromirror
Document Type
Periodical
Author
Source
Journal of Microelectromechanical Systems J. Microelectromech. Syst. Microelectromechanical Systems, Journal of. 32(4):352-361 Aug, 2023
Subject
Language
ISSN
1057-7157
1941-0158
1941-0158
Abstract
This work presents the first high-aspect-ratio alumina stiffening structures, fabricated by combining atomic layer deposition (ALD) of alumina with silicon deep reactive ion etching (Si-DRIE), designed to improve MEMS micromirror devices. By selective etching of an alumina-coated silicon mold, we produced vertical alumina fins with a depth up to $500 \mu \text{m}$ and a width down to $0.13 \mu \text{m}$ , corresponding film-aspect-ratios up to 3800. We applied this stiffening structure to a lightweight MEMS micromirror with $215 \mu \text{m}$ thickness and 2 mm diameter. We characterized the optical flatness and dynamic deformation of this device, which are quantities of interest for compact image projection systems.