AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP20
Electron Cyclotron Resonance Remote Plasma Enhanced Atomic Layer Deposition of Ruthenium Thin Films

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: M.-G. Ko, Hanyang University, South Korea
Authors: E.-J. Lee, Hanyang University, South Korea
B.-Y. Kim, Hanyang University, South Korea
S.K. Park, Hanyang University, South Korea
H.-D. Kim, Hanyang University, South Korea
J.-W. Park, Hanyang University, South Korea
M.-G. Ko, Hanyang University, South Korea
Correspondent: Click to Email
As the silicon process migrates to small device geometries, new deposition process technology will be required to solve the problems obtained with high trench capacitor and ultra thin gate oxide. Attempts to deposit material with atomic level control, atomic layer deposition as a technique which can be available good film uniformity and excellent step coverage have been reported. Ruthenium is a noble metal has low electrical resistivity, high chemical inertness, thermal stability and hardness. Especially, ALD of ruthenium thin films using the metal electrode for trench DRAM capacitor have been researched because the films have not only excellent uniformity also high work function energy of deposited films. In this study, ruthenium thin films prepared by high density plasma ALD with Ru(EtCp)@sub2@ as ruthenium precursor and NH@sub3@ gas as plasma ion source from room temperature to 400°C. ECR remote plasma as high density plasma ion source has over 10@super12@ /cm @super3@ ion density, therefore, ligands of precursor gas can be removed easily. Ruthenium thin films was grown to self-limited reaction process to be ranged from 250°C to 290°C deposited by conventional ALD on 44 nm thick TiN/ 4 nm thick Ti / 100 nm thick SiO@sub2@ / p-type (100) Si wafer. This result reveals that ALD process depends on chemical limited reaction with surface atom and precursor gas, furthermore, this temperature region possess sufficient energy to adsorb ruthenium precursor gas on substrate. Conventional ALD of ruthenium thin film deposited with oxygen and argon mixed gas as a reaction gas is formed ruthenium and ruthenium oxide, however, high-density remote plasma enhanced ALD of ruthenium deposited using NH@sub3@ as a plasma gas is formed only ruthenium films by low angle HRXRD (High Resolution X-ray Diffraction) peaks. Ruthenium thin films deposited by HDPALD have surface morphology of 10 ~ 12 Å, and electrical resistivity of 11 ~ 15 µm cm.