A novel high aspect ratio technology for MEMS fabrication using standard silicon wafers

This paper presents a novel MEMS fabrication technology based on standard single crystal silicon wafers. High aspect ratio structures are manufactured using a three mask level technology and dry processing throughout. The complete process flow is presented and a discussion of the most critical process steps is given. After processing the released micromechanical components consist of mono-crystalline silicon without additional thin films. In contrast to other solutions only one release etch step is necessary. The micromechanical components are fixed with anchor like structures. As a result of the novel process flow these anchors are surrounded by air gaps. Thus a strongly reduced parasitic capacitance with respect to bulk silicon is achieved. These air gap insulated microstructures (AIM) were fabricated and tested with respect to mechanical stability, temperature dependence and electrical behaviour of an exemplary oscillator structure. (C) 2002 Elsevier Science B.V. All rights reserved.