Title :
Maximized Benefit of La–Al–O Higher-
Gate Dielectrics by Optimizing the La/Al Atomic Ratio
Author :
Arimura, Hiroaki ; Brown, Stephen L. ; Callegari, Alessandro ; Kellock, Andrew ; Bruley, John ; Copel, Matt ; Watanabe, Heiji ; Narayanan, Vijay ; Ando, Takashi
Author_Institution :
Dept. of Mater. & Life Sci., Osaka Univ., Suita, Japan
fDate :
3/1/2011 12:00:00 AM
Abstract :
The benefit of La-Al-O higher-k gate dielectrics is maximized by optimizing the Al/(La+Al) atomic ratio. The Al/(La+Al) atomic ratio modulates the band gap, dielectric constant, and interface dipoles, resulting in change of energy band alignment. The La-Al-O film with an Al/(La+Al) atomic ratio of 0.25 yields a maximum leakage current reduction exceeding HfO2 and La2O3, owing to the optimized band alignment structure. Moreover, a SiON underlayer instead of SiO2 enables additional equivalent oxide thickness scaling down to 7.4 Å while maintaining the fully reduced leakage current with a gate-first process.
Keywords :
aluminium; hafnium compounds; high-k dielectric thin films; lanthanum compounds; leakage currents; permittivity; silicon compounds; HfO2; La-Al-O; La2O3; SiO2; SiON; atomic ratio; dielectric constant; energy band alignment; gate-first process; higher-k gate dielectrics; interface dipoles; leakage current reduction; Atomic layer deposition; Dielectrics; High K dielectric materials; Leakage current; Logic gates; Photonic band gap; Silicon; Band gap engineering; La–Al–O; gate-first process; higher- $k$ gate dielectric; interface dipole;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2010.2103043