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Work function of Ni3Si2 on HfSixOy and SiO2 and its implication for Ni fully silicided gate applications.
- Source :
- Applied Physics Letters; 1/15/2007, Vol. 90 Issue 3, p032103, 3p, 4 Graphs
- Publication Year :
- 2007
-
Abstract
- The effective work function (WF) of Ni<subscript>3</subscript>Si<subscript>2</subscript> was evaluated on HfSi<subscript>x</subscript>O<subscript>y</subscript> and SiO<subscript>2</subscript> dielectrics. Ni<subscript>3</subscript>Si<subscript>2</subscript> forms, in thin film Ni–Si diffusion couples with Ni to Si composition ratios between 1 and 2, after formation of a Ni<subscript>2</subscript>Si/NiSi stack and by its reaction at moderate thermal budgets (comparable to those used in back end processing of complementary metal-oxide-semiconductor circuits). Ni<subscript>3</subscript>Si<subscript>2</subscript> formation limits, on the Ni-rich side, the process window for NiSi fully silicided (FUSI) gates (NiSi at interface with dielectric) to reacted Ni–Si ratios <1.5. The WF of Ni<subscript>3</subscript>Si<subscript>2</subscript> was found to have similar values and behavior to that of NiSi, both on SiO<subscript>2</subscript> (showing similar modulation with dopants) and on HfSi<subscript>x</subscript>O<subscript>y</subscript>, in contrast to Ni-richer silicides such as Ni<subscript>2</subscript>Si and Ni<subscript>31</subscript>Si<subscript>12</subscript> which do not exhibit significant WF modulation with dopants on SiO<subscript>2</subscript> and have considerably higher WF on HfSi<subscript>x</subscript>O<subscript>y</subscript>. This suggests that the chemistry and structure of the original NiSi/dielectric interface are not modified significantly by the subsequent growth of Ni<subscript>3</subscript>Si<subscript>2</subscript> and implies that its formation may be tolerable when targeting NiSi FUSI gates, thereby expanding the process window for this application. [ABSTRACT FROM AUTHOR]
- Subjects :
- ELECTRON work function
DIELECTRICS
THIN films
SILICIDES
SILICON compounds
Subjects
Details
- Language :
- English
- ISSN :
- 00036951
- Volume :
- 90
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Applied Physics Letters
- Publication Type :
- Academic Journal
- Accession number :
- 32763169
- Full Text :
- https://doi.org/10.1063/1.2430687