Atomic layer deposition of hafnium silicate gate dielectric films using Hf[N (CH3)(C2H5)]4 and SiH[N(CH3)2]3 precursors

Hf-silicate gate dielectrics were formed by atomic layer deposition (ALD) technology using the liquid Hf[N(CH3)(C2H5)](4) and SiH[N(CH3)(2)](3) precursors. The advantages of these precursors as good materials is because their melting points and vapor pressures are in a comfortable working range. In SiO2 ALD film formation, the growth rate per cycle was dependent on reactor pressures between 0.5 and 5.0 Torr chamber pressure. In order to obtain a good uniformity of less than 5%, the pressures of the reactor chamber were kept at 0.5 and 5.0 Torr for ALD of HfO2 and ALD of SiO2 films, respectively. The SiH[N(CH3)(2)](3) precursor made it possible to deposit the SiO2 layers not only on SiO2 films but also on HfO2 films. Hf-silicate films were deposited at 275 degrees C using alternating HfO2 and SiO2 ALD cycles. The thickness and the Hf/(Hf + Si) compositions of Hf-silicate films could be easily controlled by the number of the deposition cycles. (c) 2005 The Electrochemical Society.