Investigation of diaphragm deflection of an absolute MEMS capacitive polysilicon pressure sensor

C. Walk; A. Goehlich; A. Giese; M. Goertz; H. Vogt; M. Kraft

doi:10.1117/12.2176188

21 May 2015 Investigation of diaphragm deflection of an absolute MEMS capacitive polysilicon pressure sensor

C. Walk, A. Goehlich, A. Giese, M. Goertz, H. Vogt, M. Kraft

Proceedings Volume 9517, Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems; 95170T (2015) https://doi.org/10.1117/12.2176188
Event: SPIE Microtechnologies, 2015, Barcelona, Spain

Abstract

This paper deals with the characteristics of circular shaped polysilicon pressure sensor diaphragms operating in the non-tactile mode. Using a phase shifting interferometer the main characteristics of diaphragms were investigated under applied pressure with respect to sensitivity, initial deflection and cavity height. Diaphragms with a thickness of 1 μm and a diameter of 96 μm were investigated in an intended pressure range of applied pressure of about 700 – 2000 hPa. Process parameters with major impact on performance and yield limitations were identified. These include the variance in diaphragm sensitivity and the impact of the variance of the sacrificial oxide layer defining the diaphragm cavity height on the contact pressure point. The sensitivity of these diaphragms including the variance was found to be - 19.8 ± 1.3 nm per 100 hPa. The impact of variance in the cavity height on the contact pressure point was found to be about 3.7 ± 0.5 hPa per nm. Summarizing both impacts a maximum variation of the contact pressure point of more than 450 hPa is possible to occur considering a nominal deflection of 300 nm. By optimizing the process of diaphragm deposition the variance in the sensitivity of the diaphragm was decreased by a factor of 2. A semi – empirical formula was evaluated that describes the deflection including initial deflection due to intrinsic stress and the process variations. A validation to the experimental obtained deflection lines showed a good agreement with deviations of less than 2 % for radial ranges of maximum deflection.

Citation Download Citation

C. Walk, A. Goehlich, A. Giese, M. Goertz, H. Vogt, and M. Kraft "Investigation of diaphragm deflection of an absolute MEMS capacitive polysilicon pressure sensor", Proc. SPIE 9517, Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems, 95170T (21 May 2015); https://doi.org/10.1117/12.2176188

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
9 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Sensors

Semiconducting wafers

Data modeling

Oxides

Microelectromechanical systems

Silicon

Low pressure chemical vapor deposition

Show All Keywords

Keywords/Phrases

Search In:

Publication Years