A process to fabricate micro‐membrane of Si₃N₄ and SiO₂ using front‐side lateral etching technology

Abstract

Purpose

To fabricate submicrometer thin membrane of silicon nitride and silicon dioxide over an anisotropically etched cavity in (100) silicon.

Design/methodology/approach

PECVD of silicon dioxide and Silcion nitride layers of compatible thicknesses followed by thermal annealing in nitrogen ambients at 1,000°C for 30 min, leads to stable membrane formation. Anisotropic etching of (100) silicon below the membrane through channels on the sides has been used with controlled cavity dimensions.

Findings

Lateral front side etching through channels slows down etching rate drastically. The etching mechanism has been discussed with experimental details.

Practical limitations/implications

Vacuum sealed cavity membranes can be realised for micro sensor applications.

Originality/value

The process is new and feasible for micro sensor technologies.

Citation

Alvi, P.A., Lourembam, B.D., Deshwal, V.P., Joshi, B.C. and Akhtar, J. (2006), "A process to fabricate micro‐membrane of Si₃N₄ and SiO₂ using front‐side lateral etching technology", Sensor Review, Vol. 26 No. 3, pp. 179-185. https://doi.org/10.1108/02602280610675456