Ge2Sb2Te5 (GST) films were deposited on TiN(50 nm)/SiO2/Si substrates and trench structures of TiAlN(100 nm)/Si with various deposition parameters by metal organic chemical vapor deposition (MOCVD). Hexagonal GST films were deposited at temperatures of 330-370 degrees C, deposition pressure of 40 Torr, bubbling temperatures of Ge(50 degrees C), Sb(10 degrees C), and Te(30 degrees C) precursors. Germanium incorporation into GST films by MOCVD is sensitively influenced by deposition parameters such as deposition pressure, deposition temperature, and bubbling temperatures of precursors. Trench structures with a diameter of 120 nm and a height of 200 nm are completely filled by GST MOCVD. (c) 2006 American Institute of Physics.