Highly conductive SnO2 thin films deposited by atomic layer deposition using tetrakis-dimethyl-amine-tin precursor and ozone reactant

Abstract

Highly conductive SnO2 thin films were grown by atomic layer deposition (ALD) in a wide growth temperature range (50°C–250°C), using a tetrakis-dimethyl-amine tin (TDMASn) precursor and an ozone reactant. The ozone SnO2 ALD thin films showed excellent electrical properties (5.63×10−4Ωcm) over 200°C, but the electrical properties of the films were not measured at low growth temperature (under 125°C). In order to verify the origin of the electrical properties as a function of growth temperature, the growth behavior and chemical bonding states, film crystallinity, surface roughness, and optical properties were examined. The ALD ozone SnO2 thin films deposited above the 200°C growth temperature had high carrier concentration (3.2×1020–1.2×1021) and Hall mobility (~32cm2V/s). Also, films deposited at 250°C exhibited a polycrystalline structure and high transmittance (over 80% at 550nm wavelength). As a transparent conductive oxide material, the film properties of ALD ozone SnO2 thin films are very suitable due to their excellent high conductivity and reasonable transmittance.