AVS 49th International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuP

Paper TF-TuP9
Analysis of Stresses in Ru Thin Films Deposited by MOCVD

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Poster Session
Presenter: H.J. Lim, Seoul National University, Korea
Authors: H.J. Lim, Seoul National University, Korea
S.Y. Kang, Seoul National University, Korea
C.S. Hwang, Seoul National University, Korea
H.J. Kim, Seoul National University, Korea
Correspondent: Click to Email
Ru is the most promising material for the capacitor electrode in the next generation DRAMs. Ru thin films, however, which are deposited by chemical vapor deposition have high tensile stresses. So many problems in respect of device reliability such as peeling or thermal deformation have been reported. In this study, we investigated the effects of the various deposition parameters on the stress behavior. Ru thin films were prepared by MOCVD on Si substrate using RuCp(i-PrCp) precursor and O@sub 2@ reaction gas. The stresses of films were measured using laser scanning method. The tensile stress increased with reduction of substrate temperature. And in thicker films, larger tensile stress appeared. These tendencies are attributed to low atomic mobility of the Ru material(T@sub m@=2523K). Also tensile stress increased after annealing. It can be explained by volume shrinkage through rearrangement of grain boundary having less density during annealing. Based on these results, we propose the mechanism of this stress behavior with quantitative analysis. Then the experiments to reduce these stresses were performed by control of oxygen gas flow rate. The addition of the excess oxygen suppressed the grain growth, leading to reduction of tensile stress effectively.