Samsung Advanced Institute of Technology

We propose a novel selective atomic layer deposition (ALD) process for depositing MoS₂ using MoCl₅ and H₂S precursors. On the SiO₂ surface, the prolonged introduction of MoCl₅ vapor by increasing the MoCl₅ pulsing time rapidly suppressed the subsequent MoS₂ growth owing to the intense self-etching effect of MoCl₅, that is, the detachment of weakly bonded surface adsorbates (MoCl_x*). In contrast, the Al surface allowed stronger adsorption of MoCl₅ than in case of the SiO₂ surface, and thus, effectively compensated for the reduced deposition rate. By optimizing the MoCl₅ pulsing time, we demonstrated the self-aligned growth of MoS₂ on pre-defined Al (5 nm) patterns (circular and letter patterns) on a SiO₂ substrate with a negligible selectivity loss. Moreover, it was found that area-selective deposition could be maintained up to 400 ALD cycles.