Title :
HfO/sub 2/ for strained-Si and strained-SiGe MOSFETs
Author :
Yousif, M.Y.A. ; Johansson, M. ; Lundgren, P. ; Bengtsson, S. ; Sundqvist, J. ; Hårsta, A. ; Radamson, H.H.
Author_Institution :
Dept. of Microtechnology & Nanoscience, Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
We report on HfO/sub 2/ gate dielectrics grown by atomic layer deposition (ALD) at 600/spl deg/C on strained-Si and strained-SiGe layers. The strain status in the Si layer remained unaltered after HfO/sub 2/ deposition and an interface state density of /spl sim/1/spl times/10/sup 11/ cm/sup -2/ eV/sup -1/ was obtained for the case of thick HfO/sub 2/ films. The breakdown fields were in the range 2-5 MV/cm, which is high compared to HfO/sub 2/ films grown at higher temperatures. The leakage current was reduced by more than five orders of magnitude for the case of a thin HfO/sub 2/ film with an EOT of 1.25 nm and ultra-thin cap (2.5-3 nm) layers on Si/sub 0.77/Ge/sub 0.23//Si. The carrier transport through these HfO/sub 2/ films was found to follow Frenkel-Poole emission over a wide range of applied gate voltage.
Keywords :
Ge-Si alloys; MOSFET; Poole-Frenkel effect; atomic layer deposition; dielectric thin films; elemental semiconductors; hafnium compounds; interface states; leakage currents; semiconductor device breakdown; semiconductor materials; silicon; 1.25 nm; 2.5 to 3 nm; 600 degC; ALD; EOT; Frenkel-Poole emission; HfO/sub 2/-Si; HfO/sub 2/-SiGe; applied gate voltage; atomic layer deposition; breakdown fields; carrier transport; high-k gate dielectrics; interface state density; leakage current; strained-Si MOSFET; strained-SiGe MOSFET; ultra-thin cap layers; Atomic layer deposition; Capacitive sensors; Dielectrics; Electric breakdown; Hafnium oxide; Interface states; Leakage current; Semiconductor films; Temperature distribution; Voltage;
Conference_Titel :
European Solid-State Device Research, 2003. ESSDERC '03. 33rd Conference on
Conference_Location :
Estoril, Portugal
Print_ISBN :
0-7803-7999-3
DOI :
10.1109/ESSDERC.2003.1256862
