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Comparison of CoW/SiO<sub>2</sub> and CoB/SiO<sub>2</sub> Interconnects from the Perspective of Electrical and Reliability Characteristics
oleh: Yi-Lung Cheng, Kai-Hsieh Wang, Chih-Yen Lee, Giin-Shan Chen, Jau-Shiung Fang
Format: | Article |
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Diterbitkan: | MDPI AG 2023-02-01 |
Deskripsi
As the feature size of integrated circuits has been scaled down to 10 nm, the rapid increase in the electrical resistance of copper (Cu) metallization has become a critical issue. To alleviate the resistance increases of Cu lines, co-sputtered CoW and CoB alloying metals were investigated as conductors and barriers in this study. Annealing CoM (M = W or B)/SiO<sub>2</sub>/<i>p</i>-Si structures reduced the resistivity of CoM alloys, removed sputtering-deposition-induced damage, and promoted adhesion. Additionally, both annealed CoW/SiO<sub>2</sub> or CoB/SiO<sub>2</sub> structures displayed a negligible V<sub>fb</sub> shift from capacitance-voltage measurements under electrical stress, revealing an effective barrier capacity, which is attributed to the formation of MO<sub>x</sub> layers at the CoM/SiO<sub>2</sub> interface. Based on the thermodynamics, the B<sub>2</sub>O<sub>3</sub> layer tends to form more easily than the WO<sub>x</sub> layer. Hence, the annealed CoB/SiO<sub>2</sub>/<i>p</i>-Si MIS capacitor had a higher capacitance and a larger breakdown strength did than the annealed CoW/SiO<sub>2</sub>/<i>p</i>-Si MIS capacitor.