skip to main content

SciTech ConnectSciTech Connect

Title: Standing and sitting adlayers in atomic layer deposition of ZnO

The extent of reactivity of diethyl zinc (DEZ) with a hydroxylated surface during atomic layer deposition (ALD) of ZnO using DEZ and water is measured. Two adlayer configurations of DEZ are possible. The “standing” adlayer releases one ethyl group from DEZ. The “sitting” adlayer releases both ethyl groups, thus forming a Zn bridge between two O anions. Density functional theory calculations suggest the sitting configuration is more stable than the standing configuration by 790 meV. In situ quadrupole mass spectroscopy of by-product ethane generated in ALD half cycles indicate that ∼1.56 OH sites react with a DEZ molecule resulting in 71.6% of sitting sites. A simple simulation of a “ball-and-stick” DEZ molecule randomly collapsing on a neighboring site remarkably captures this adlayer behavior. It is concluded that DEZ fraction sitting is a competitive process of a standing DEZ molecule collapsing onto an available neighboring hydroxyl site, as sites vie for occupancy via adsorption and surface diffusion.
Authors:
;  [1] ; ;  [2] ;  [3] ;  [4] ;  [5]
  1. Department of Mechanical Engineering & Material Science, Washington University in St. Louis, Missouri 63130 and Institute of Materials Science & Engineering, Washington University in St. Louis, Missouri 63130 (United States)
  2. Department of Mechanical Engineering & Material Science, Washington University in St. Louis, Missouri 63130 (United States)
  3. Department of Physics, Washington University in St. Louis, Missouri 63130 (United States)
  4. SAFC Hitech, 1429 Hilldale Ave., Haverhill, Massachusetts 01832 (United States)
  5. Institute of Materials Science & Engineering, Washington University in St. Louis, Missouri 63130 and Department of Physics, Washington University in St. Louis, Missouri 63130 (United States)
Publication Date:
OSTI Identifier:
22489775
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films; Journal Volume: 34; Journal Issue: 1; Other Information: (c) 2015 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; DENSITY FUNCTIONAL METHOD; ETHANE; MASS SPECTROSCOPY; MEV RANGE 100-1000; MOLECULES; SURFACES; ZINC; ZINC OXIDES