Atomic Layer Deposition of Hafnium Silicate Thin Films Using HfCl 2[N(SiMe3)2]2 and H2O

Abstract

Hafnium silicate thin films were deposited on Si substrate for alternative gate dielectrics by atomic layer deposition (ALD) using a single metallorganic precursor, dichlorobis[bis(trimethylsilyl)amido]hafnium (HfCl 2[N(SiMe3)2]2), and H2O as an oxidant in the temperature range of 150-400°C. The effect of pulse time for purge and precursor injection confirmed the self-limiting characteristic of ALD. Film growth rate and composition were investigated as a function of deposition temperature. Growth rate reached to a maximum value of 1.3 A ̊/cycle at 250°C and rapidly decreased to 0.3 Å/cycle at 400°C. The composition analysis of as-deposited films using X-ray photoelectron spectroscopy showed that the composition ratio of Si/(Hf + Si) increased linearly from 0.15 to 0.3 as the deposition temperature increased. © 2004 The Electrochemical Society. All rights reserved.