
Proceedings Paper
CMOS integrable micromirrors with highly improved drift-stabilityFormat | Member Price | Non-Member Price |
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Paper Abstract
The large-scale integration of analog operable MEMS micro-mirrors onto active CMOS address circuitry requires high
quality planar reflective optical surfaces but also a stable deflection vs. voltage characteristic. However, for
implementing a CMOS compatible surface micromachining process, certain obstacles like a restricted thermal budget
and a limited selection of suitable materials must be overcome. In this paper, amorphous TiAl is presented as a new
actuator material for monolithical MEMS integration onto CMOS circuitry at room temperature. Sputter deposited TiAl
has an x-ray amorphous structure and a low stress gradient. The missing long range order and the high melting point help
to virtually eliminate stress relaxation effects, i.e. TiAl hinges behave almost perfectly elastic. In a first study, 40 &mgr;m
wide piston mirrors have been implemented onto substrates with fixed wired address electrode arrays. The actuators had
a 300 nm TiAl core sandwiched between two layers of 25 nm Al. The devices reach a maximum deflection of about 500
nm at a dc voltage of about 23V. The drift-stability of the deflection has been tested at "worst case" conditions close to
the deflection limit. During 30 min of continuous deflection near 500 nm a mechanical drift below 25nm has been
observed. TiAl offers the perspective for actuators capable of a stable analog operation, which is essential to many
applications, such as adaptive optics.
Paper Details
Date Published: 9 February 2007
PDF: 11 pages
Proc. SPIE 6467, MEMS Adaptive Optics, 64670R (9 February 2007); doi: 10.1117/12.707630
Published in SPIE Proceedings Vol. 6467:
MEMS Adaptive Optics
Scot S. Olivier; Thomas G. Bifano; Joel A. Kubby, Editor(s)
PDF: 11 pages
Proc. SPIE 6467, MEMS Adaptive Optics, 64670R (9 February 2007); doi: 10.1117/12.707630
Show Author Affiliations
Jan U. Schmidt, Fraunhofer Institute of Photonic Microsystems (Germany)
Jens Knobbe, Fraunhofer Institute of Photonic Microsystems (Germany)
Jens Knobbe, Fraunhofer Institute of Photonic Microsystems (Germany)
Andreas Gehner, Fraunhofer Institute of Photonic Microsystems (Germany)
Hubert Lakner, Fraunhofer Institute of Photonic Microsystems (Germany)
Hubert Lakner, Fraunhofer Institute of Photonic Microsystems (Germany)
Published in SPIE Proceedings Vol. 6467:
MEMS Adaptive Optics
Scot S. Olivier; Thomas G. Bifano; Joel A. Kubby, Editor(s)
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