A wet release process for fabricating slender and compliant suspended micro-mechanical structures

• Published in: Sensors and actuators. A, Physical Vol. 103; no. 1; pp. 202 - 212
• Main Authors: Pamidighantam, S, Laureyn, W, Rusu, C, Baert, K, Puers, R, Tilmans, H.A.C
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 15.01.2003; Elsevier Science
• Subjects: Applied sciences; Compliance; Contact angle; DTS; Electronics; Exact sciences and technology; Micro- and nanoelectromechanical devices (mems/nems); SAM; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Slenderness ratio; Stiction; Surface micro-machining; DTS; Compliance; Stiction; Slenderness ratio; Contact angle; Surface micro-machining; SAM; Self-assembled layer; Atomic force microscopy; Scanning electron microscopy; Micromachining; Aluminium; Experimental study; Micromechanical devices; Wet process; Manufacturing process; Germanium; Silicon; Microelectromechanical device; X-ray photoelectron spectra
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(02)00350-3

This paper reports on the development of a generic wet release process for the fabrication of suspended slender and compliant micro-mechanical structures of poly-SiGe, poly-Si and aluminium with thickness values in the range 0.5–2 μm and gap spacing from 0.5 to 2 μm, respectively. A self-assembled monolayer (SAM) of n-decyltrichlorosilane (DTS) is used as an anti-stiction material. Process characterisation studies include DTS SAM characterisation, release of polycrystalline silicon germanium test structures, polycrystalline silicon device structures on silicon substrate and Aluminium test structures on AF45 glass substrate. We have obtained work of adhesion values of 0.06, 11, and 1 μJ/m 2, slenderness ratio (SR) values of 3464, 752.2, and 2061, compliance ( C) of 2100, 12, and 120 m/N, and contact angle of 129°, 126°, and 110.3°, for poly-SiGe, poly-Si and aluminium cantilevers respectively. Our results compare favourably well with results from the literature.