Ultrathin Al2O3 Gate Dielectric Engineering on MoS2 for 2D Materials Based Devices
Successful realization of high-performance 2D-based devices requires ultrathin and pinhole free dielectric films. With the assistance of reactive ozone species, we deposited thin uniform Al2O3 by atomic layer deposition (ALD) and also deposited low-k organic and inorganic OTS-Al hybrid dielectric films on MoS2 by molecular ALD (MALD). In addition to the excellent film uniformity and conformity as revealed by AFM images, the interfacial chemical composition and lattice structure characterization using XPS, Raman, HR-TEM also show a undetectable interfacial oxidation states and lattice disorder to the MoS2 surface, owing to its enhanced surface hydrophilicity and better chemical stability towards ozone exposure. The electrical results of MoS2 devices suggest that these films have promising dielectric properties, such as low leakage current (~10(-5) A/cm2) and minimal doping effects. Both ALD and MALD processes are common processes in the semiconductor industry, and their application to the deposition of dielectric films on 2D materials can be easily scaled to a production environment.