Atomic Layer Deposition of HfO2, TiO2, and HfxTi1-xO2 Using Metal (Diethylamino) Precursors and H2O

Tetrakis (diethylamino) hafnium (TDEAH), tetrakis (diethylamino) titanium (TDEAT), and H2O were used for the atomic layer deposition (ALD) of HfO2, TiO2, and HfxTi1-xO2 films on silicon substrates. The ALD temperature windows were found to be 175-250 degrees C for HfO2 (0.12 nm/cycle) and 150-250 degrees C for TiO2 (similar to 0.06 nm/cycle). The 175-250 degrees C overlap region is ideal for the ALD of the HfxTi1-xO2 films. Different compositions of HfxTi1-xO2 were obtained by varying the [TDEAH/H2O]/[TDEAT/H2O] cycle ratios, and excellent tunability of film composition was found using X-ray photoelectron spectroscopy (XPS). The HfxTi1-xO2 deposition rate was found to be the superposition of the two individual growth rates. Both as-deposited and postdeposition annealed films were studied with XPS, phase shift interferometry, and grazing incidence X-ray diffraction. As-deposited HfO2 and TiO2 films were found to be amorphous, and they began to crystallize after annealing at 600 degrees C in the monoclinic phase (HfO2) and in weak anatase phase (TiO2). The HfxTi1-xO2 films remained amorphous after annealing up to about 1000 degrees C in N-2 for 5 min. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3522758] All rights reserved.