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Optimization of Poly-SiGe Deposition Processes for Modular MEMS Integration

Published online by Cambridge University Press:  01 February 2011

Blake C.-Y. Lin ,
Tsu-Jae King  and
Roger T. Howe
Blake C.-Y. Lin
Affiliation:
University of California at Berkeley, Berkeley, CA 94720, U.S.A.
Tsu-Jae King
Affiliation:
University of California at Berkeley, Berkeley, CA 94720, U.S.A.
Roger T. Howe
Affiliation:
Dept. of Electrical Engineering and Computer Sciences, Berkeley Sensor and Actuator Center
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Abstract

This paper describes a bi-layer deposition technique to reduce the strain gradient of polycrystalline silicon-germanium (poly-SiGe) thin films without the use of any post-deposition annealing. By adjusting deposition conditions such as temperature, pressure, and/or flow rates of reactants, poly-SiGe films with required low average stresses can be obtained. Using the bi-layer technique, a strain gradient of 1.1×10-5 μm-1 (equivalent to 88 mm radius-of-curvature) has been achieved in 3.9 μm-thick poly-SiGe. This strain gradient would cause only 0.055 μm tip deflection for a 100 μm-long cantilever. The thermal budget was ∼10 hours at 425 °C, and no post-deposition annealing was required. The bi-layer film also exhibits low compressive average stress (-36 MPa) and low resistivity (0.55 mΩ-cm).

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 782: Symposium A – Micro- and Nanosystems , 2003 , A2.4
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

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