Atomic Layer Deposition of HfO[sub 2], TiO[sub 2], and Hf[sub x]Ti[sub 1−x]O[sub 2] Using Metal (Diethylamino) Precursors and H[sub 2]O

Abstract

Tetrakis (diethylamino) hafnium (TDEAH), tetrakis (diethylamino) titanium (TDEAT), and H2O were used for the atomic layer deposition (ALD) of HfO2, TiO2, and Hfx Ti1-x O2 films on silicon substrates. The ALD temperature windows were found to be 175-250°C for Hf O2 (0.12 nm/cycle) and 150-250°C for Ti O2 (∼0.06 nm/cycle). The 175-250°C overlap region is ideal for the ALD of the Hfx Ti1-x O2 films. Different compositions of Hfx Ti1-x O2 were obtained by varying the [TDEAH/ H2 O] / [TDEAT/ H2 O] cycle ratios, and excellent tunability of film composition was found using X-ray photoelectron spectroscopy (XPS). The Hfx Ti1-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 Hf O2 and Ti O2 films were found to be amorphous, and they began to crystallize after annealing at 600°C in the monoclinic phase (Hf O2) and in weak anatase phase (Ti O2). The Hfx Ti1-xO2 films remained amorphous after annealing up to about 1000°C in N2 for 5 min. © 2010 The Electrochemical Society.