Abrupt breakdown in dielectric/metal gate stacks: a potential reliability limitation?
Authors:
- M. ChoMCM. Cho
- B. KaczerBKB. Kaczer
- Ph. RousselPRPh. Roussel
- G. GroesenekenGGG. Groeseneken
- H. MaesHMH. Maes
- S. De GendtSGS. De Gendt
- 19 September 2005
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Electron Device Letters
- Vol. 26 (10) , 773-775
Abstract
In downscaled poly-Si gate MOSFET devices reliability margin is gained by progressive wearout. When the poly-Si gate is replaced with a metal gate, the slow wearout phase observed in ultrathin SiON and HfSiON dielectrics with poly-Si gate disappears, and with it, the reliability margin. We demonstrate for several combinations of dielectric and gate materials that the large abrupt current increase (/spl Delta/I) as compared to poly-Si is not likely due to process issues, but is an intrinsic property of the dielectric/metal gate stack. The occurrence of large /spl Delta/I is a potential limitation for the reliability of metal gate devices.Keywords
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