Wafer-Scale Growth and Integration of Two-Dimensional Transition Metal Dichalcogenides

So far, two-dimensional (2D) transition metal dichalcogenides (TMDs) have received great attention for their use as channels in electronic devices. The confined charges in atomically thin channels allow improved electrostatic gate control and reduced short-channel effects, which could facilitate continued transistor scaling. However, the integration of 2D TMDs with Si CMOS platforms has been a great challenge owing to the lack of high-throughput and large-scale production, proper characterization and integration processes for TMDs.<br/>In this talk, we present our works on the growth, characterization, and integration of 2D TMDs. First, we demonstrate high-throughput production of 6~8-inch wafer-scale monolayer MoS₂ and WS₂ via a pulsed metalorganic chemical vapor deposition technique, using Mo(CO)₆, W(CO)₆, and (C₂H₅)₂S₂ as precursors. Periodic interruption of the precursor supply allowed successful regulation of secondary nucleation even under high growth rates, and as a result, wafer-scale monolayer MoS₂ and WS₂ were obtained within 12 min. Second, we present non-destructive characterization of wafer-scale TMDs. In particular, we used spectroscopic ellipsometry for analyzing both TMD and the dielectric thin film deposited on TMD at the same time. Third, we exhibit integration of TMDs as a channel of the field-effect transistor (FET). Thanks to the well-stitched continuous structure over the whole wafer, the as-grown TMDs can be transferred onto any desired substrate with minimal degradation via reliable wafer-scale de-bonding and bonding processes. On the basis of our transferred TMD films, we demonstrate 8-inch wafer-scale batch fabrication of FETs via standard photolithography, and they showed uniform electrical performance with &gt; 90% yield. Additional challenges on materials growth and device fabrication will also be discussed.