Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9670523 | Microelectronic Engineering | 2005 | 9 Pages |
Abstract
New failure mechanisms associated with breakdown in high-k gate stack consisting of HfO2/SiOx bilayered structure are presented. In addition to dielectric-breakdown-induced epitaxy (DBIE) commonly found in breakdowns in poly-Si/SiOxNy and poly-Si/Si3N4 MOSFETs, grain-boundary and field-assisted breakdowns near the poly-Si edge are found. A model based on breakdown induced thermo-chemical reactions has been developed to describe the physical microstructural damages triggered by breakdown in the high-k gate stack and the associated post-breakdown electrical performance. Some abnormal post-breakdown electrical behaviors such as recouping of the transistor's saturated drain current, percolation resistance and transconductance are found to be common for high-k MOSFETs. Grain-boundary enhanced breakdown in annealed HfO2 films is of critical importance in degrading the reliability of high-k gate stacks.
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Computer Science
Hardware and Architecture
Authors
K.L. Pey, R. Ranjan, C.H. Tung, L.J. Tang, V.L. Lo, K.S. Lim, T.A/L. Selvarajoo, D.S. Ang,