Mechanical properties and reliability of aluminum nitride thin films

Elmeri Österlund, Jere Kinnunen, Ville Rontu, Altti Torkkeli, Mervi Paulasto-Kröckel

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Knowledge of the mechanical properties and fatigue behavior of thin films is important for the design and reliability of microfabricated devices. This study uses the bulge test to measure the residual stress, Young's modulus, and fracture strength of aluminum nitride (AlN) thin films with different micro-structures prepared by sputtering, metalorganic vapor phase epitaxy (MOVPE), and atomic layer deposition (ALD). In addition, the fatigue behavior is studied under cyclic loading. The results indicate that the fracture strength and Young's modulus of AlN are mainly determined by the film microstructure, which is consecutively influenced by the deposition method and conditions. A microstructure with a higher order of crystallinity has increased fracture strength and Young's modulus. Additionally, the strength limiting defects are located at the film-substrate interface. The measured residual stresses were 249, 876, 1,526, and 272 MPa for two sputtered films of different thicknesses, MOVPE and ALD films, respectively. The fracture strengths were 1.42, 1.54, 2.76, and 0.61 GPa, and Young's moduli were 335, 343, 346, and 272 GPa. No clear signs of fatigue were observed after 10,000 cycles at a load corresponding to 83% of the fracture strength. (C) 2018 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)306-313
Number of pages8
JournalJournal of Alloys and Compounds
Volume772
Early online date10 Sep 2018
DOIs
Publication statusPublished - 25 Jan 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • mechanical properties
  • Nitride materials
  • Thin films
  • Microstructure
  • Mechanical properties
  • SINGLE
  • ELASTIC PROPERTIES
  • HIGH-TEMPERATURE
  • SILICON
  • FRACTURE STRENGTH
  • ALN BUFFER
  • CRYSTAL PLASTICITY
  • MEMS
  • STRESS
  • ATOMIC LAYER DEPOSITION

Fingerprint Dive into the research topics of 'Mechanical properties and reliability of aluminum nitride thin films'. Together they form a unique fingerprint.

  • Projects

    InForMed: An integrated pilot line for micro-fabricated medical devices

    Paulasto-Kröckel, M., Österlund, E., Dong, H. & Broas, M.

    01/06/201531/05/2019

    Project: Business Finland: Other research funding

    Equipment

    OtaNano

    Anna Rissanen (Manager)

    Aalto University

    Facility/equipment: Facility

  • Cite this