Title :
The impact of sub monolayers of HfO/sub 2/ on the device performance of high-k based transistors [MOSFETs]
Author :
Ragnarsson, Lars-Ake ; Pantisano, L. ; Kaushik, V. ; Saito, S.-I. ; Shimamoto, Y. ; De Gendt, S. ; Heyns, M.
Author_Institution :
IMEC, Leuven, Belgium
Abstract :
Thin layers of ALCVD/spl trade/ HfO/sub 2/ were deposited on top of 1.5 nm SiON. At 5 growth cycles - resulting in less than 1 monolayer of HfO/sub 2/ - the mobility is as low as 70% of the SiON control. Simulation results show that a fixed charge density of 3/spl times/10/sup 13/ cm/sup -2/ at the poly-Si/HfO/sub 2/ interface can explain this behavior. Two different kinds of poly-Si - in situ doped and implanted - result in different inversion capacitance. Both poly-Si varieties show similar VT shifts and mobility reduction. However, for in situ doped poly-Si, no poly depletion is observed whereas for implanted poly-Si it is.
Keywords :
MOSFET; atomic layer deposition; carrier mobility; chemical vapour deposition; dielectric thin films; elemental semiconductors; hafnium compounds; silicon; 1.5 nm; ALCVD; HfO/sub 2/ sub monolayers; Si-HfO/sub 2/; SiON; carrier mobility; charge density; doped polysilicon; high-k based transistors; implanted polysilicon; inversion capacitance; mobility reduction; poly depletion; poly-Si/HfO/sub 2/ interface; Capacitance; Capacitance-voltage characteristics; Degradation; Delay estimation; Dielectric measurements; Hafnium oxide; High K dielectric materials; High-K gate dielectrics; Scattering; Thickness measurement;
Conference_Titel :
Electron Devices Meeting, 2003. IEDM '03 Technical Digest. IEEE International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-7872-5
DOI :
10.1109/IEDM.2003.1269172
