Atomic Layer Deposition of Ultrathin LaO/AlO Nanolaminates on MoS with Ultraviolet Ozone Treatment.

Due to the chemically inert surface of MoS, uniform deposition of ultrathin high-κ dielectric using atomic layer deposition (ALD) is difficult. However, this is crucial for the fabrication of field-effect transistors (FETs). In this work, the atomic layer deposition growth of sub-5 nm LaO/AlO nanolaminates on MoS using different oxidants (HO and O) was investigated. To improve the deposition, the effects of ultraviolet ozone treatment on MoS surface are also evaluated. It is found that the physical properties and electrical characteristics of LaO/AlO nanolaminates change greatly for different oxidants and treatment processes. These changes are found to be associated with the residual of metal carbide caused by the insufficient interface reactions. Ultraviolet ozone pretreatment can substantially improve the initial growth of sub-5 nm HO-based or O-based LaO/AlO nanolaminates, resulting in a reduction of residual metal carbide. All results indicate that O-based LaO/AlO nanolaminates on MoS with ultraviolet ozone treatment yielded good electrical performance with low leakage current and no leakage dot, revealing a straightforward approach for realizing sub-5 nm uniform LaO/AlO nanolaminates on MoS.