Comparison between Hf-silicate films deposited by ALD with BDMAS [SiH2(N(CH3)2] and TDMAS [SiH(N(CH3)2)3] precursors

Thin hafnium (Hf) silicate films were deposited by alternating HfO2 and SiO2 layers with atomic layer deposition (ALD) technique. Hf(N(CH3)(C2H5))(4) was used for HfO2 layer, and bis(dimethylamino)silane [BDMAS: SiH2(N(CH3)(2))(2)] or tris(dimethylamino )silane [TDMAS: SiH(N(CH3)(2))(3)] precursors were used for SiO2 layers, respectively. O-3 was used as an oxidant. The thickness of SiO2 deposited using ALD process is controlled by the number of growth cycles and the growth rate per cycle was different for each precursor, that for BDMAS being 1.5 times that for TDMAS at the same reactor pressure. Furthermore, the thickness and the Hf/(Hf + Si) compositions of ALD Hf-silicate films deposited using BDMAS and TDMAS precursors can be easily controlled by the number of growth cycles. The carbon impurity in the Hf-silicate film deposited using BDMAS was about an order of magnitude less than that using for TDMAS. (c) 2005 The Electrochemical Society.