Journal
IEEE ELECTRON DEVICE LETTERS
Volume 26, Issue 4, Pages 231-233Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/LED.2005.844701
Keywords
CMOS; laminated metal gate; metal gate; metal nitride; work function
Categories
Ask authors/readers for more resources
This letter presents a novel technique for tuning the work function of a metal gate electrode. Laminated metal gate electrodes consisting of three ultrathin (similar to 1-nm) layers, with metal nitrides (HfN, TiN, or TaN) as the bottom and top layers and element metals (Hf, Ti, or Ta) as the middle layer, were sequentially deposited on SiO2, followed by rapid thermal annealing annealing. Annealing of the laminated metal gate stacks at high temperatures (800 degrees C-1000 degrees C) drastically increased their work functions (as much as 1 eV for HfN-Ti-TaN at 1000 degrees C). On the contrary, the bulk metal gate electrodes (HfN, TiN and TaN) exhibited consistent midgap work functions with only slight variation under identical annealing conditions. The work function change of the laminated metal electrodes is attributed to the crystallization and the grain boundary effect of the laminated structures after annealing. This change is stable and not affected by subsequent high-temperature process. The three-layer laminated metal gate technique provides PMOS-compatible work functions and excellent thermal stability even after annealing at 1000 degrees C.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available