Title :
Covalent Nature in La-Silicate Gate Dielectrics for Oxygen Vacancy Removal
Author :
Kawanago, Takamasa ; Kakushima, Kuniyuki ; Ahmet, Parhat ; Tsutsui, Kazuo ; Nishiyama, Akira ; Sugii, Nobuyuki ; Natori, Kenji ; Hattori, Takeo ; Iwai, Hiroshi
Author_Institution :
Frontier Res. Center, Tokyo Inst. of Technol., Yokohama, Japan
fDate :
3/1/2012 12:00:00 AM
Abstract :
This letter focuses on studying the characteristic behavior of oxygen in La-silicate dielectrics by comparison with HfO2 dielectrics. VFB shift of La-silicate caused by oxygen annealing is found to be stable even after reduction annealing unlike with HfO2. Moreover, reduced gate leakage current and improved effective mobility of nMOSFETs with La-silicate are observed by oxygen incorporation, suggesting the annihilation of oxygen vacancy. Since the oxygen in La-silicate covalently exists adjacent to the Si atom, stability of oxygen in La-silicate can be understood in terms of strong bonding of covalent nature.
Keywords :
MOSFET; annealing; electron mobility; high-k dielectric thin films; lanthanum compounds; leakage currents; oxygen; La-silicate gate dielectrics; La2O3; Si; VFB shift; covalent bond; gate leakage current reduction; high-k gate dielectrics; nMOSFET mobility; oxygen annealing; oxygen stability; oxygen vacancy annihilation; oxygen vacancy removal; reduction annealing; Annealing; Bonding; Dielectrics; Hafnium compounds; Logic gates; Silicon; $hbox{HfO}_{2}$ ; Covalent nature; La-silicate; high-$k$ gate dielectrics; ionic nature; oxygen vacancy;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2178111
