Low temperature Ga2O3 atomic layer deposition using gallium tri-isopropoxide and water

Abstract

Ga2O3 atomic layer deposition (ALD) was carried out using gallium tri-isopropoxide (GTIP) as a gallium source and H2O as an oxygen source at a low temperature (150 degrees C). The Ga2O3 ALD films show amorphous, smooth, and transparent behavior. The growth behavior and a variety of optical, structural, and electrical properties were investigated by various measurements. The growth behavior of Ga2O3 ALD using GTIP reveals a typical ALD process, and Ga2O3 films on glass substrates show outstanding transmittance (over 90%). The Ga:O ratio was measured as 1: 1.7 by the Rutherford backscattering spectrometry, and auger electron spectroscopy confirmed that there was no carbon impurity (under the detection limit). The surface morphology was investigated through an atomic force microscope analysis, and all of the films deposited at 150, 200, and 250 degrees C showed smooth and featureless characteristics. Ga2O3 ALD thin film shows excellent leakage current (1 x 10(-11) A at 1 MV/cm) and a very suitable breakdown field (6.5-7.6 MV/cm) as compared to previously reported Ga2O3 films. Also, the dielectric constant of the films is similar to that of conventional Ga2O3 films (about 9.23).