Band alignment issues in metal/dielectric stacks: a combined photoemission and inverse photoemission study of the HfO 2/Pt and HfO 2/Hf systems
Date
2004Source Title
Proceedings of the International Symposium on Advanced Short-time Thermal Processing for Si-based CMOS Devices II
Publisher
Electrochemical Society
Volume
1
Pages
255 - 263
Language
English
Type
Conference PaperItem Usage Stats
140
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21
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Abstract
We have studied the HfO 2/Hf and HfO 2/Pt systems by photoemission and inverse photoemission spectroscopies. It is found that the "effective workfunction" of metals in multilayer structures are different than their vacuum workfunctions and are modified by their interface dipoles at the metal/high-k interface. The effective workfunction of Hf is 4.4 eV whereas that of Pt is 5.3 eV, within the range of acceptable values for PMOS and NMOS respectively.
Keywords
Band alignmentsDielectric stacks
Photoemission spectroscopy
Work functions
CMOS integrated circuits
Electric insulators
Fermi level
Gates (transistor)
Hafnium compounds
Multilayers
Photoemission
Thermodynamic stability
Threshold voltage
Dielectric materials