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 degrees C-250 degrees 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 x 10(-4) Omega cm) over 200 degrees C, but the electrical properties of the films were not measured at low growth temperature (under 125 degrees 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 degrees C growth temperature had high carrier concentration (3.2 x 10(20)-1.2 x 10(21)) and Hall mobility (similar to 32 cm(2) V/s). Also, films deposited at 250 degrees C exhibited a polycrystalline structure and high transmittance (over 80% at 550 nm 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.