AVS 52nd International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP3
Investigation of Annealing Effect and Suppression of Hydration and Silicate Formation of La@sub 2@O@sub 3@ Thin Films

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Electronic Materials and Processing Poster Session
Presenter: D. Eom, Seoul National University, Korea
Authors: D. Eom, Seoul National University, Korea
S.Y. No, Seoul National University, Korea
C.S. Hwang, Seoul National University, Korea
H.J. Kim, Seoul National University, Korea
Correspondent: Click to Email
High dielectric constant materials (high-K) have attracted a great deal of interest because of the dramatic scaling down of Metal-Oxide-Semiconductor field effect transistor (MOSFET) device reaching its physical limit in terms of reduction of thickness. Among high-k materials, such as Al@sub 2@O@sub 3@, HfO@sub 2@, HfSiO@sub 4@, ZrO@sub 2@, La@sub 2@O@sub 3@ etc., have attracted a great deal of interest as a replacement for the conventional SiO@sub 2@ gate oxide. La@sub 2@O@sub 3@ is promising as a gate dielectric film in future CMOS devices because it has a large conduction band offset(~2.0eV), high didelectric constant(24~27) and good leakage current characteristic. However La@sub 2@O@sub 3@ films appears to be hydrated easily and become silicate films by react with Si substrate. Moreover improvement of thermal stability is needed like other high-k films. In this work AlN thiln films was deposited after La@sub 2@O@sub 3@ film deposition on Si substrate to suppress hydration of La@sub 2@O@sub 3@ films. From X-ray Photoelectron Spectroscopy(XPS) results the hydration was not shown. AlN thin film was also deposited on Si substrate before La@sub 2@O@sub 3@ film deposition as a barrier material to prevent reaction of La2O3 film with Si substrate. Without thermal annealing, AlN barrier film is effective to reduce silicate formation, but after 800@super o@C annealing the AlN film mixed with La@sub 2@O@sub 3@ film therefore barrier effect disappeared. And There were flat band shift toward negative voltage and degradation of electrical properties after annealing at 800@super o@C and over. From Auger Electron Spectroscopy and XPS results, it is considered to be because of a generation of oxygen vacancy during annealing. Low temperature annealing at O@sub 2@ ambient after 800@super o@C annealing recovered flat band voltage and electrical characteristics.