Process study of gadolinium aluminate atomic layer deposition fromthegadolinium tris-di-isopropylacetamidinate precursor

Abstract

The growth of gadolinium aluminate films by atomic layer deposition from gadolinium tris-di-isopropylacetamidinate and trimethylaluminium was studied. The consequences of using water versus ozone as the oxidant were studied. The effects of pulse lengths, metal source ratios, and temperature were noted. Depositing two cycles of gadolinium oxide per cycle of aluminum oxide was found to yield films with a stiochiometry of Gd1.04AlO3 and a growth rate of 2.2 Å in aggregate for each set of gadolinium and aluminum cycles. The deposition rate was found to be stable between 210 and 325 °C. The use of ozone instead of water as the oxygen source was found to reduce the film uniformity. The densities ranged from 3 to 6 g/cm3 depending on the Gd content of the films. The impurity contamination of the films was measured by secondary ion mass spectrometry and infrared absorption and found consistent with carboxylated species. Theextracted bandgap for the Gd1.04AlO3 films was 5.8 eV. The films were amorphous as deposited.