Ruthenium Films Prepared by Liquid Source Metalorganic Chemical Vapor Deposition Using Ru(dpm)3 Dissolved with Tetrahydrofuran Solvent

Abstract

Ruthenium films were prepared on SiO2/Si substrates by liquid source metalorganic chemical vapor deposition (LSMOCVD) using Ru(C11H19O2)3 (tris (dipivaloylmethanato) ruthenium: Ru(dpm)3) precursor dissolved in C4H8O (tetrahydrofuran: THF) solvent as a liquid source. The deposited films consisted of metallic ruthenium in single phase under all deposition conditions studied and could be directly deposited on SiO2 without having a distinct incubation time. We elucidated that the deposition mechanism was controlled by an oxygen-controlled surface reaction on the basis of its strong dependence on the oxygen concentration above 300°C. Good step coverage of over 70% for film deposited on a concave structure with an aspect ratio of ten was obtained in the oxygen-controlled surface reaction region. Therefore, the Ru films deposited by LSMOCVD using Ru(dpm)3 dissolved in THF solvent are effective for use as capacitor electrodes in gigabit dynamic random access memories (DRAMs).