Fabrication of keyhole-free ultra-deep high-aspect-ratio isolation trench and its applications
File version
Author(s)
Yan, GZ
Fan, J
Zhou, J
Liu, XS
Li, ZH
Wang, YY
Griffith University Author(s)
Primary Supervisor
Other Supervisors
Editor(s)
Date
Size
File type(s)
Location
License
Abstract
An ultra-deep (40–120 µm) keyhole-free electrical isolation trench with an aspect ratio of more than 20:1 has been fabricated. The process combines DRIE (deep reactive ion etch), LPCVD insulating materials refilling and TMAH or KOH backside etching technologies. Employing multi-step DRIE with optimized etching conditions and a sacrificial polysilicon layer, the keyholes in trenches are prevented; as a result the mechanical strength and reliability of isolation trenches are improved. Electrical tests show that such an isolation trench can electrically isolate the MEMS structures effectively from each other and from on-chip detection circuits. The average resistance in the range of 0–100 V is more than 1012 Ω, and the breakdown voltage is above 205 V. This technology has been successfully employed in the fabrication of the monolithic integrated bulk micromachining MEMS gyroscope.
Journal Title
Journal of Micromechanics and Microengineering
Conference Title
Book Title
Edition
Volume
15
Issue
3
Thesis Type
Degree Program
School
Publisher link
Patent number
Funder(s)
Grant identifier(s)
Rights Statement
Rights Statement
Item Access Status
Note
Access the data
Related item(s)
Subject
Engineering
Microelectromechanical systems (MEMS)