Abstract
Photoelectron spectroscopy and transmission electron microscopy provide clear experimental evidence to show that oxygen initially present in the W gate layer of a metal/high-k gate stack is transferred to the substrate and increases the interfacial oxide during post-deposition thermal processing, Oxide interface layer growth was reduced, but still occurred, if a TaN barrier layer was used to cap the W gate metal, thus minimizing atmospheric oxygen incorporation. Our results suggest that oxygen is incorporated into the W layer (perhaps at grain boundaries and interfaces) during or immediately after its deposition, thus providing a source for subsequent oxidation of the underlying layers. This effect, which may be exhibited by other high workfunction metals besides W, may be an important contributor to the Vfb instability observed in scaled PMOS devices based on the metal/high-k gate stacks.
Original language | English (US) |
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Title of host publication | ECS Transactions - 5th International Symposium on High Dielectric Constant Materials and Gate Stacks |
Pages | 213-218 |
Number of pages | 6 |
Volume | 11 |
Edition | 4 |
DOIs | |
State | Published - 2007 |
Externally published | Yes |
Event | 5th International Symposium on High Dielectric Constant Materials and Gate Stacks - 212th ECS Meeting - Washington, DC, United States Duration: Oct 8 2007 → Oct 10 2007 |
Other
Other | 5th International Symposium on High Dielectric Constant Materials and Gate Stacks - 212th ECS Meeting |
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Country/Territory | United States |
City | Washington, DC |
Period | 10/8/07 → 10/10/07 |
ASJC Scopus subject areas
- Engineering(all)