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Title: Local residual stress monitoring of aluminum nitride MEMS using UV micro-Raman spectroscopy

Localized stress variation in aluminum nitride (AlN) sputtered on patterned metallization has been monitored through the use of UV micro-Raman spectroscopy. This technique utilizing 325 nm laser excitation allows detection of the AlN E2(high) phonon mode in the presence of metal electrodes beneath the AlN layer with a high spatial resolution of less than 400 nm. The AlN film stress shifted 400 MPa from regions where AlN was deposited over a bottom metal electrode versus silicon dioxide. Thus, across wafer stress variations were also investigated showing that wafer level stress metrology, for example using wafer curvature measurements, introduces large uncertainties for predicting the impact of AlN residual stress on the device performance.
 [1] ;  [2]
  1. The Pennsylvania State Univ., University Park, PA (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0960-1317; 617639
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Micromechanics and Microengineering. Structures, Devices and Systems
Additional Journal Information:
Journal Volume: 26; Journal Issue: 2; Journal ID: ISSN 0960-1317
IOP Publishing
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
42 ENGINEERING; aluminum nitride; microelectromechanical systems; Piezoelectric transducers; Raman scattering; stress measurement