Low temperature (<100°C) deposition of aluminum oxide thin films by ALD with O3 as oxidant

Al2O3 films were deposited by atomic layer deposition (ALD) using trimethylaluminum and O-3 as precursor and oxidant, respectively, at growth temperatures ranging from room temperature to 300 degrees C on Si(100) substrates. Growth rate and refractive index of the Al2O3 films decreased from 0.20 to 0.08 nm/cycle and increased from 1.52 to 1.65, respectively, with increasing growth temperature. The dielectric constant slightly increased from 6.8 to 8 with increasing growth temperature in the same temperature range. Al2O3 films grown using O-3 as oxidant show a smaller hysteresis, lower leakage current density, and higher breakdown field strength compared to those using H2O as oxidant at the same growth temperature. X-ray photoelectron spectroscopy showed that the films grown at lower temperatures have a smaller bandgap energy. The Al2O3 films grown at a temperature as low as 100 degrees C showed reasonable dielectric properties for dielectric film applications on flexible substrates. (c) 2006 The Electrochemical Society.