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US 7,598,549 B2Granted
Semiconductor device having a silicon layer in a gate electrode
AssigneeElpida Memory, Inc.
InventorsSatoru Yamada, Ryo Nagai
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Abstract
A CMOS device includes a silicon substrate, a gate insulating film, and a gate electrode including a silicon layer doped with boron and phosphorous, a tungsten nitride layer and a tungsten layer. A ratio of a maximum boron concentration to a minimum boron concentration in a boron concentration profile across the thickness of the silicon layer is not higher than 100. The CMOS device has a lower NBTI (Negative Bias Temperature Instability) degradation.
Claims7
A semiconductor device comprising:
- a semiconductor substrate;
- a gate insulating film formed on said semiconductor substrate;
- and
- a gate electrode including a silicon layer as a bottom layer formed on said gate insulating film, said silicon layer being doped with phosphorous and boron,
- wherein a ratio of a maximum boron concentration to a minimum boron concentration in a boron concentration profile across a thickness of said silicon layer is not higher than 100, and
- wherein said gate electrode has a round bottom edge.
3 more elements
Dependencies are inferred from the claim text.