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Effects of Al2O3 Dielectric Cap and Nitridation on Device Performance, Scalability, and Reliability for Advanced High-k/Mëtal Gate pMOSFET Applications.
- Source :
- IEEE Transactions on Electron Devices; Oct2007, Vol. 54 Issue 10, p2738-2749, 12p, 10 Black and White Photographs, 2 Charts, 17 Graphs
- Publication Year :
- 2007
-
Abstract
- A pFET threshold-voltage (V<subscript>t</subscript>) reduction of about 200 mV is demonstrated by inserting a thin Al<subscript>2</subscript>O<subscript>3</subscript> layer between the high-K dielectric and the TiN gate without noticeable degradation of other electrical properties. HfSiO<subscript>x</subscript> capped with 9 Å of Al<subscript>2</subscript>O<subscript>3</subscript> obtains a low long-channel V<subscript>t</subscript> of —0.37 V (the lowest among those with TiN gate), a high mobility of 59 cm<superscript>2</superscript> ⁄V · s at 0.8 MV/cm (92% of universal value), a negligible equivalent. oxide-thickness (EOT) increase of 0.1 Å (compared to the uncapped reference), and a low V<subscript>t</subscript> instability of 4.8 mV at 7 MV/cm. It also passes the ten-year negative-bias-temperature-instability (NBTI) lifetime specification with a gate overdrive of —0.7 V. This indicates that Al<subscript>2</subscript>O<subscript>3</subscript> caps are beneficial to the pFET applications. In contrast, nitrogen incorporation in the Al<subscript>2</subscript>O<subscript>3</subscript>-capped HfSiO<subscript>x</subscript> is not favorable because it increases the V<subscript>t</subscript> by 50—140 mV, degrades the mobility by 10%-22%, increases the EOT by 0.5—0.8 Å and the V<subscript>t</subscript> instability by 5–13 mV, and reduces the NBTI lifetime by four to five orders of magnitude. Compared to postcap nitridation, posthigh-k nitridation results in more severe degradation of these properties by incorporating nitrogen closer to the Si/SiO<subscript>2</subscript> interface. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00189383
- Volume :
- 54
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Electron Devices
- Publication Type :
- Academic Journal
- Accession number :
- 26953928
- Full Text :
- https://doi.org/10.1109/TED.2007.904478