Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1590816 | Science and Technology of Advanced Materials | 2007 | 6 Pages |
Abstract
We systematically investigated intrinsic and extrinsic thermal reactions at TiN/HfSiON gate stacks. The formation of an ultrathin TiO2 interlayer was found to be an intrinsic reaction at the metal/insulator interface, but growth of SiO2 underlayers between HfSiON and Si substrates, which determines the electrical thickness of metal-oxide-semiconductor (MOS) devices, depends on the structure and deposition method of the gate electrodes. Physical vapor deposition (PVD) grown TiN electrodes covered with W overlayers exhibited excellent thermal stability at up to 1000 °C. Formation of ultrathin TiO2 interlayers reduced gate leakage current (Ig), and growth of the oxide underlayer was suppressed by less than a few angstroms even for 1000 °C annealing. In contrast, we found that halogen impurities within CVD-grown metal electrodes enhance interface SiO2 growth, resulting in deterioration of equivalent oxide thickness (EOT) versus Ig characteristics of the gate stacks.
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Shiniti Yoshida, Yasumasa Watanabe, Yuuki Kita, Takayoshi Shimura, Heiji Watanabe, Kiyoshi Yasutake, Yasushi Akasaka, Yasuo Nara, Keisaku Yamada,