Sticking probabilities of H 2 O and Al(CH 3 ) 3 during atomic layer deposition of Al 2 O 3 extracted from their impact on film conformality

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Karsten Arts
  • Vincent Vandalon
  • Riikka Puurunen

  • Mikko Utriainen
  • Feng Gao
  • Wilhelmus M.M. Erwin Kessels
  • Harm C.M. Knoops

Research units

  • Eindhoven University of Technology
  • VTT Technical Research Centre of Finland
  • Oxford Instruments Group Plc

Abstract

The conformality of a film grown by atomic layer deposition (ALD) is strongly affected by the reactivities of the precursor and coreactant, which can be expressed in terms of their sticking probabilities toward the surface. We show that the leading front of the thickness profile in high-aspect-ratio structures gives direct information on the sticking probabilities of the reactants under most conditions. The slope of the front has been used to determine the sticking probabilities of Al(CH 3 ) 3 and H 2 O during ALD of Al 2 O 3 . The determined values are (0.5-2) × 10 -3 for Al(CH 3 ) 3 and (0.8-2) × 10 -4 for H 2 O at a set-point temperature of 275 °C, corresponding to an estimated substrate temperature of ∼220 °C. Additionally, the thickness profiles reveal soft-saturation behavior during the H 2 O step, most dominantly at reduced temperatures, which can limit the conformality of Al 2 O 3 grown by ALD. This work thus provides insights regarding quantitative information on sticking probabilities and conformality during ALD, which is valuable for gaining a deeper understanding of ALD kinetics.

Details

Original languageEnglish
Article number030908
Number of pages5
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume37
Issue number3
Publication statusPublished - 24 Apr 2019
MoE publication typeA1 Journal article-refereed

ID: 33937805