Influence of O(³P)/O₂ Flux on the Atomic Layer Deposition of B₂O₃ Using Trimethyl Borate at Room Temperature

Abstract

Oxygen plasma is crucial to many atomic layer deposition (ALD) processes, and O( 3 P) radicals play a significant role in terms of reactivity and surface modification. In situ X-ray photoelectron spectroscopy (XPS), residual gas analysis mass spectrometry (RGA-MS), and ab initio molecular dynamics (AIMD) simulations were used to study the free-radical-assisted ALD of boron oxide (B 2 O 3 ) films on Si( 100) using trimethyl borate [B(OCH 3 ) 3 ] and mixed O( 3 P)/O 2 effluents at room temperature at varying levels of O( 3 P)/O 2 flux to the surface. Under these conditions, no reaction with pure O 2 was observed. The XPS results show that at low O( 3 P)/O 2 flux, a complete removal of alkyl ligands is observed and C-free B 2 O 3 is achieved, with CO 2 and H 2 O as the main reaction products. At higher O( 3 P)/O 2 fluxes, the formation of a stable oxidized C surface layer is observed with some C incorporation into the growing B 2 O 3 film. In both flux regimes, the B 2 O 3 film thickness increased linearly with the number of cycles, consistent with an ALD process. AIMD simulations of O( 3 P) collisions with B(OCH 3 ) 3 indicate a multistep ligand removal mechanism initiated by hydrogen abstraction at a threshold O( 3 P) energy of ∼0.1 eV, consistent with RGA-MS results. In contrast, C oxidation and incorporation in the high-flux regime result from O 2 termination of the O( 3 P)-induced C radical sites. This work demonstrates that the purity of B 2 O 3 films, efficiency of ligand removal, and surface reaction products can be flux-dependent.

Stabilization of the surface and lattice structure for LiNi0.83Co0.12Mn0.05O2via B2O3 atomic layer deposition and post-annealing

“…2e, for 2B SC83 particles, a small and broad B 1s peak occurs around 192.0 eV. It is lower than the B 1s peak of B 2 O 3 at 192.6–193.0 eV, 41–43 but higher than the B 1s peak of LiBO x at 190.9–191.8 eV, 44–46 which indicates that B 2 O 3 and LiBO x coexist on the surface of the 2B SC83 particles. The formation of LiBO x is attributed to B 2 O 3 ALD on the surface LiOH.…”