Open AccessTiN/PECVD‐Si 3 N 4 /TiN diaphragm‐based capacitive‐type MEMS acoustic sensor
Author(s) -
Lee J.,
Jeon J.H.,
Kim Y.G.,
Lee S.Q.,
Yang W.S.,
Lee J.S.,
Lee S.G.
Publication year - 2016
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2015.3856
Subject(s) - tin , capacitive sensing , materials science , capacitance , plasma enhanced chemical vapor deposition , optoelectronics , microelectromechanical systems , sensitivity (control systems) , diaphragm (acoustics) , voltage , electronic engineering , electrical engineering , chemical vapor deposition , electrode , engineering , chemistry , metallurgy , loudspeaker
A capacitive‐type MEMS acoustic sensor with a planarised TiN/plasma‐enhanced chemical vapour deposition ‐Si 3 N 4 /TiN diaphragm based on a polyimide sacrificial layer is presented. The multi‐layer diaphragm has the effective residual stress of +31.5 MPa. Furthermore, this sensor features a 21% lower parasitic capacitance and a 56% lower air‐gap resistance in comparison with those of a sensor fabricated without planarisation. Five photomasks were used. In addition, to evaluate the frequency response, both an effective capacitance model and an equivalent circuit model equipped with a voltage‐controlled voltage source are newly proposed and compared with conventional models. The open‐circuit sensitivity is modelled to −45.4 dBV/Pa at 1 kHz with 9.6 V, indicating a difference of 0.9 dB in comparison with the open‐circuit sensitivity of the conventional model.