Standing and sitting adlayers in atomic layer deposition of ZnO

Journal Article · Fri Jan 15 04:00:00 EST 2016 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4938080· OSTI ID:22489775

Gao, Zhengning; Banerjee, Parag ^[1]; Wu, Fei; Myung, Yoon ^[2]; Fei, Ruixiang ^[3]; Kanjolia, Ravindra ^[4]; Yang, Li ^[5]

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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)

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.

• OSTI ID: 22489775
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films Journal Issue: 1 Vol. 34; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANIONS
DENSITY FUNCTIONAL METHOD
ETHANE
MASS SPECTROSCOPY
MEV RANGE 100-1000
MOLECULES
SURFACES
ZINC
ZINC OXIDES