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

This study describes a modified atomic layer deposition (ALD) process for fabricating BiO x Se y 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 2 Se 3 and a plasma-enhanced ALD process for Bi 2 O 3 , a method for the sequential deposition of Bi 2 SeO 5 ternary films has been established. The thin film has been deposited on SiO 2 and TiN substrates, exhibiting growth rates of 0.17 to 0.16 nm·cycle -1 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 -1 ), demonstrating their potential as a dielectric layer.