Title :
The impact of la-doping on the reliability of low Vth high-k/metal gate nMOSFETs under various gate stress conditions
Author :
Kang, C.Y. ; Young, C.D. ; Huang, J. ; Kirsch, P. ; Heh, D. ; Sivasubramani, P. ; Park, H.K. ; Bersuker ; Lee, B.H. ; Choi, H.S. ; Lee, K.T. ; Jeong, Y.H. ; Lichtenwalner, J. ; Kingon, A.I. ; Tseng, H.-H. ; Jammy, R.
Author_Institution :
SEMATECH, Austin, TX
Abstract :
La-doped HfSiO samples show lower threshold voltage (Vth) and gate current (Igate), which is attributed to dipole formation at the high-k/SiO2 interface. At low and intermediate field stress, La-doped devices exhibit better immunity to positive bias temperature instability (PBTI) due to their lower charge trapping efficiency than the control HfSiO, which mainly results from a dipole-induced greater barrier offset. However, the primary cause for defect generation at high field stress is attributed to the La atoms in the interfacial SiO2 layer. By optimizing the technique to incorporate nitrogen into the bottom interface, this high field reliability issue can be minimized while maintaining good device characteristics.
Keywords :
MOSFET; doping; hafnium compounds; lanthanum; semiconductor device reliability; silicon compounds; HfSiO:La; charge trapping efficiency; defect generation; dipole formation; gate current; gate stress; greater barrier offset; metal gate nMOSFET; positive bias temperature instability; Atomic layer deposition; Degradation; Doping; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; MOSFETs; Stress control; Temperature control; Threshold voltage;
Conference_Titel :
Electron Devices Meeting, 2008. IEDM 2008. IEEE International
Conference_Location :
San Francisco, CA
Print_ISBN :
978-1-4244-2377-4
Electronic_ISBN :
8164-2284
DOI :
10.1109/IEDM.2008.4796628
