AVS 49th International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeA

Paper AS-WeA7
Chlorine and Oxygen Transport in ALD Grown ZrO@sub 2@ and HfO@sub 2@ Films on Silicon

Wednesday, November 6, 2002, 4:00 pm, Room C-106

Session: High-k Dielectric Characterization
Presenter: S. Ferrari, Lab. MDM - INFM, Italy
Authors: S. Ferrari, Lab. MDM - INFM, Italy
G. Scarel, Lab. MDM - INFM, Italy
C. Wiemer, Lab. MDM - INFM, Italy
S. Spiga, Lab. MDM - INFM, Italy
M. Fanciulli, Lab. MDM - INFM, Italy
Correspondent: Click to Email
ZrO@sub 2@ and HfO@sub 2@ have received a lot of attention as possible candidates to replace SiO@sub 2@ as insulating layers in CMOS structures. Oxygen diffusivity in those materials may affect a number of properties. Among them, oxygen stoichiometry in the oxide, interfacial silicon oxide formation/reduction are critical parameters that need to be controlled in order to succesfully build high-k based devices with the desired properties. The growth of ZrO@sub 2@ and HfO@sub 2@ films by means of Atomic Layer Deposition (ALD) from ZrCl@sub 4@ And HfCl@sub 2@ percursors is known to cause significant incorporation of chlorine. Chlorine may have detrimental effects on the electrical properties of the films, by introducing positive charge in the film and possibly localized states in the band gap. In this paper we study oxygen and chlorine diffusion by means of Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) in ZrO@sub 2@ and HfO@sub 2@ films as a function of annealing temperature in different environment gasses such as N@sub 2@ and O@sub 2@ . Preliminary results show that in oxygen deficient environment chlorine desorption in inhibited, demonstrating that chlorine can out-diffuse by exchange with the oxygen. HfO@sub 2@ shows a limited oxygen and chlorine mobility as compared to ZrO@sub 2@.