“Zincone” Zinc Oxide−Organic Hybrid Polymer Thin Films Formed by Molecular Layer Deposition

Abstract

Hybrid organic−inorganic polymer thin films of the form (−O−Zn−O−C2H4−)n have been deposited from diethyl zinc and ethylene glycol using molecular layer deposition (MLD) over a range of substrate temperatures between 100 and 170 °C. Infrared transmission confirms that the films consist of Zn−O and ethylene-oxide units. In analogy with known alucone polymers of the form (−O−Al−O−R−)n, the zinc-based hybrid material is an example of a “zincone” polymer. In situ quartz crystal microbalance analysis indicated that the sequential surface reactions of diethyl zinc and ethylene glycol are sufficiently self-limiting and saturating to enable well-controlled MLD growth. Quantitative analysis of in situ quartz crystal microbalance and film thickness results indicate that ethylene glycol molecules can undergo a “double reaction” where the OH groups on both ends of the diol react with available Zn−C2H5 surface sites to produce a relatively inert bridging alkane. The mass uptake per MLD cycle during Zn−hybrid film depo...