Cyclic PECVD of Ge[sub 2]Sb[sub 2]Te[sub 5] Films Using Metallorganic Sources

Abstract

Ge2Sb2Te5Ge2Sb2Te5 (GST) thin films were deposited on SiO2∕SiSiO2∕Si and TiN∕SiTiN∕Si substrates by cyclic metallorganic chemical vapor deposition using Ge(i-C4H9)4Ge(i-C4H9)4 , Sb(i-C3H7)3Sb(i-C3H7)3 , Te(i-C3H7)2Te(i-C3H7)2 as Ge, Sb, and Te precursors, respectively, with the help of Ar+H2Ar+H2 plasma at temperatures ranging from 180 to 290°C290°C . The application of plasma power was essential in obtaining a high growth rate and stoichiometric GST thin films. The chemical composition of the films was properly controlled by the cycling ratio and sequence of each precursor pulse. The stoichiometric films grown at 200°C200°C showed a smooth surface morphology, highest density, and lowest impurity concentration. GST film was selectively grown inside the contact hole having a TiN∕WTiN∕W plug.