Elastic and fracture properties of free-standing amorphous ALD Al2O3 thin films measured with bulge test

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Ville Rontu, Anton Nolvi, Ari Hokkanen, Edward Haeggström, Ivan Kassamakov. Sami Franssila
Publication year: 2018
Journal: Materials Research Express
Journal acronym: MATER RES EXPRESS
Volume number: 5
Number of pages: 10
ISSN: 2053-1591


We have investigated elastic and fracture properties of amorphous Al2O3 thin films deposited by atomic layer deposition (ALD) with bulge test technique using a free-standing thin film membrane and extended applicability of bulge test technique. Elastic modulus was determined to be 115 GPa for a 50 nm thick film and 170 GPa for a 15 nm thick film. Residual stress was 142 MPa in the 50 nm Al2O3 film while it was 116 MPa in the 15 nm Al2O3 film. Density was 3.11 g cm(-3) for the 50 nm film and 3.28 g cm(-3) for the 15 nm film. Fracture strength at 100 hPa s(-1) pressure ramp rate was 1.72 GPa for the 50 nm film while for the 15 nm film it was 4.21 GPa, almost 2.5-fold. Fracture strength was observed to be positively strain-rate dependent. Weibull moduli of these films were very high being around 50. The effective volume of a circular film in bulge test was determined from a FEM model enabling future comparison of fracture strength data between different techniques.


Atomic layer deposition, bulge testing, fracture strength

Last updated on 2020-28-09 at 03:19

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