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Proceedings Paper

Ge and GeOx films as sacrificial layer for MEMS technology based on piezoelectric AlN: etching and planarization processes
Author(s): J. Sangrador; J. Olivares; E. Iborra; L. Vergara; M. Clement; A. Sanz-Hervas
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Paper Abstract

In this article we present a study of deposition and etching techniques of germanium (Ge) and amorphous oxygen germanium (GeOx) films, with the aim of using them as sacrificial layer in the fabrication of AlN-based MEMS by surface micromachining processes. The Ge and GeOx layers were deposited by RF magnetron sputtering in Ar and Ar/O2 atmospheres. By controlling the process parameters we were able to set the final composition of the GeOx films, which was assessed by FTIR measurements. We have studied the etch rates of GeOx films with x ranging from 0 to 1 in H2O2 and H2O2/acid solutions. Depending on the etching temperature and the oxygen content in the layers, etch rates ranging from 0.2 to 2 μm/min were obtained. Nearly stoichiometric germanium oxide (GeO2) was etched in pure H2O at very high rate (>1 μm/min at room temperature). We have also developed a chemomechanical polishing (CMP) process for the planarization of Ge and GeOx. The influence of the slurries containing diverse powders (CeO2, Al2O3) and chemical agents (NH4OH, HCl), the different pads, and the various process parameters on the removal rate and the final sample topography has been studied. Finally, we have analysed the compatibility of the materials involved in the process flow with the processes of planarization and removal of the sacrificial layers.

Paper Details

Date Published: 1 July 2005
PDF: 15 pages
Proc. SPIE 5836, Smart Sensors, Actuators, and MEMS II, (1 July 2005); doi: 10.1117/12.608244
Show Author Affiliations
J. Sangrador, Univ. Politecnica de Madrid (Spain)
J. Olivares, Univ. Politecnica de Madrid (Spain)
E. Iborra, Univ. Politecnica de Madrid (Spain)
L. Vergara, Univ. Politecnica de Madrid (Spain)
M. Clement, Univ. Politecnica de Madrid (Spain)
A. Sanz-Hervas, Univ. Politecnica de Madrid (Spain)

Published in SPIE Proceedings Vol. 5836:
Smart Sensors, Actuators, and MEMS II
Carles Cane; Jung-Chih Chiao; Fernando Vidal Verdu, Editor(s)

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