Direct Growth of Bi<sub>2</sub>SeO<sub>5</sub> Thin Films for High-k Dielectrics via Atomic Layer Deposition.

Park, Hyeonbin; Hwang, Jae Hun; Oh, Seung Hoon; Ryu, Jin Joo; Jeon, Kanghyeok; Kang, Minsoo; Chai, Hyun-Jun; Ham, Ayoung et al. · ACS Nano · 2024

basic_science · Level V

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Abstract

This study describes a modified atomic layer deposition (ALD) process for fabricating BiO<sub><i>x</i></sub>Se<sub><i>y</i></sub> thin films, targeting their application as high-k dielectrics in semiconductor devices, especially for two-dimensional semiconductors. Using an intermediate-enhanced ALD technique for Bi<sub>2</sub>Se<sub>3</sub> and a plasma-enhanced ALD process for Bi<sub>2</sub>O<sub>3</sub>, a method for the sequential deposition of Bi<sub>2</sub>SeO<sub>5</sub> ternary films has been established. The thin film has been deposited on SiO<sub>2</sub> and TiN substrates, exhibiting growth rates of 0.17 to 0.16 nm·cycle<sup>-1</sup> without an incubation period, thanks to facile nucleation characteristics. The resulting film exhibited high flatness and reached 96% of its theoretical density, forming a uniform nanocrystalline structure. Electrical evaluations using metal-insulator-metal capacitors indicated the dielectric constant (∼17.6) and electrical breakdown strength (2.6 MV·cm<sup>-1</sup>), demonstrating their potential as a dielectric layer.