Protective coatings of hafnium dioxide by atomic layer deposition for microelectromechanical systems applications

Research output: Contribution to journalArticle


  • Maria Berdova
  • Claudia Wiemer
  • Alessio Lamperti
  • Grazia Tallarida
  • Elena Cianci
  • Luca Lamagna
  • Stefano Losa
  • Silvia Rossini
  • Roberto Somaschini
  • Salvatore Gioveni
  • Marco Fanciulli
  • Sami Franssila

Research units

  • CNR
  • STMicroelectronics
  • University of Milano-Bicocca
  • Institute for Microelectronics and Microsystems


This work presents the investigation of HfO2 deposited by atomic layer deposition (ALD) from either HfD-CO4 or TEMAHf and ozone for microelectromechanical systems (MEMS) applications, in particular, for environmental protection of aluminum micromirrors. This work shows that HfO2 films successfully protect aluminum in moist environment and at the same time retain good reflectance properties of underlying material. In our experimental work, the chemical composition, crystal structure, electronic density and roughness of HfO2 films remained the same after one week of humidity treatment (relative humidity of 85%, 85 °C). The reflectance properties underwent only minor changes. The observed shift in reflectance was only from 80-90% to 76-85% in 400-800 nm spectral range when coated with ALD HfO2 films grown with Hf(NMeEt)4 and no shift (remained in the range of 68-83%) for films grown from (CpMe)2Hf(OMe)Me.


Original languageEnglish
Pages (from-to)470-476
Number of pages7
JournalApplied Surface Science
Publication statusPublished - 15 Apr 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • Atomic layer deposition, Hafnium dioxide, HfO, Humidity treatment, Reflectance

ID: 2485803