AAO aids the development of Atomic Layer Deposition of conformal NiO films

NiO is an important wide bandgap p-type semiconductor with a wide range of applications. A research team led by Aalto University Professor of Chemistry and Materials Science Maarit Karppinen and Nagoya University Professor of Physics Ichiro Terasaki has published results utilizing diketonate metal precursors for Atomic Layer Deposition (ALD) of NiO films in order to precisely control the film thickness and doping with Co, Cu and Mn. While substrates like glass and Si were utilized, the researchers also took advantage of the high-aspect ratio pores of InRedox AAO to optimize ALD pulse and purge times and confirm that conformal coating could be achieved in 1 µm and 2 µm deep pores. Using nanoporous AAO films on Al foil, the team was able demonstrate the viability of their technique to coat complex structures. For applications as ALD reference substrate, AAO films on Al foil can be conveniently cleaved and imaged in an SEM, clearly revealing the uniformity and conformality of the coating.

Microstructure and optical properties of ultra-thin NiO films grown by atomic layer deposition
DJ Hagen, TS Tripathi, I Terasaki, M Karppinen, 2018 Semiconductor Science and Technology, 33(11), 115015.

NiO ALD film in nanoporous AAO

Role of AAO in this study:

  • used as a low cost reference substrate featuring high-aspect ratio pores with controlled aspect ratio
  • AAO pore diameter and pore depth could be varied to mimic high surface area, high aspect ratio structure of complex and expensive substrates
  • ALD conformality and depth uniformity is easily observable by SEM of AAO on Al