SU-8 cantilever with integrated pyrolyzed glass-like carbon piezoresistor

Jongmoon Jang; Giulia Panusa; Giovanni Boero; Juergen Brugger

doi:10.1038/s41378-022-00351-9

SU-8 cantilever with integrated pyrolyzed glass-like carbon piezoresistor

Microsyst Nanoeng. 2022 Feb 10:8:22. doi: 10.1038/s41378-022-00351-9. eCollection 2022.

Authors

Jongmoon Jang^{1

2}, Giulia Panusa³, Giovanni Boero¹, Juergen Brugger¹

Affiliations

¹ Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
² Department of Functional Ceramics, Korea Institute of Materials Science (KIMS), 51508 Changwon, Republic of Korea.
³ Optics Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.

Abstract

Glass-like carbon (GC) is a nongraphitizing material composed entirely of carbon atoms produced from selected organic polymer resins by controlled pyrolysis in an inert atmosphere. The GC properties are a combination of the properties of glass, ceramic, and graphite, including hardness, low density, low thermal conductivity, high chemical inertness, biocompatibility, high electrical conductivity, and microfabrication process compatibility. Despite these unique properties, the application of GC in mechanical sensors has not been explored thus far. Here, we investigate the electrical, structural, and chemical properties of GC thin films derived from epoxy-based negative photoresist SU-8 pyrolyzed from 700 to 900 °C. In addition, we fabricated microGC piezoresistors pyrolyzed at 700 and 900 °C and integrated them into nonpyrolyzed SU-8 cantilevers to create microelectromechanical systems (MEMS) mechanical sensors. The sensitivities of the GC sensor to strain, force, surface stress, and acceleration are characterized to demonstrate their potential and limits for electromechanical microdevices.

Keywords: Electrical and electronic engineering; Materials science.