Fatigue test results on 15 lm thick polysilicon specimens are presented and discussed, both quantitatively and qualitatively. The test structure is a newly designed, electrostatically actuated, MEMS device that allows the execution of on-chip fatigue and fracture tests on polysilicon specimens. The experiments have been carried out through a new analog, low-noise and low-perturbing electrostatic position measurement system for capacitive MEMS sensors. The setup allows for a real time monitoring of MEMS position, from which a macroscopic quantity, the elastic stiffness of the specimen, can be continuously evaluated, provided that the applied force is known. The results obtained in the present research put in evidence the decrease of the elastic stiffness during fatigue life before rupture. In addition, the stress amplitude during the load cycles plays a role on the lifetime of the test devices: larger stress amplitudes around a tensile mean stress reduce the fatigue resistance, mainly when a compressive stress is also present, in good agreement with a Wöhler curve.

A new on-chip test structure for real time fatigue analysis in polysilicon MEMS

LANGFELDER, GIACOMO;LONGONI, ANTONIO FRANCESCO;ZARAGA, FEDERICO;CORIGLIANO, ALBERTO;GHISI, ALDO FRANCESCO;
2009

Abstract

Fatigue test results on 15 lm thick polysilicon specimens are presented and discussed, both quantitatively and qualitatively. The test structure is a newly designed, electrostatically actuated, MEMS device that allows the execution of on-chip fatigue and fracture tests on polysilicon specimens. The experiments have been carried out through a new analog, low-noise and low-perturbing electrostatic position measurement system for capacitive MEMS sensors. The setup allows for a real time monitoring of MEMS position, from which a macroscopic quantity, the elastic stiffness of the specimen, can be continuously evaluated, provided that the applied force is known. The results obtained in the present research put in evidence the decrease of the elastic stiffness during fatigue life before rupture. In addition, the stress amplitude during the load cycles plays a role on the lifetime of the test devices: larger stress amplitudes around a tensile mean stress reduce the fatigue resistance, mainly when a compressive stress is also present, in good agreement with a Wöhler curve.
sezele
File in questo prodotto:
File Dimensione Formato  
MR-09-published.pdf

Accesso riservato

: Altro materiale allegato
Dimensione 1.68 MB
Formato Adobe PDF
1.68 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/545084
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 25
  • ???jsp.display-item.citation.isi??? 22
social impact