MoS2 thin films from a (NtBu)2(NMe2)2Mo and 1-propanethiol atomic layer deposition process

Potential commercial applications for transition metal dichalcogenide (TMD) semiconductors such as MoS2 rely on unique material properties that are only accessible at monolayer to few-layer thickness regimes. Therefore, production methods that lend themselves to the scalable and controllable formation of TMD films on surfaces are desirable for high volume manufacturing of devices based on these materials. The authors have developed a new thermal atomic layer deposition process using bis(tert-butylimido)-bis(dimethylamido) molybdenum and 1-propanethiol to produce MoS2-containing amorphous films. They observe a self-limiting reaction behavior with respect to both the Mo and S precursors at a substrate temperature of 350 degrees C. Film thickness scales linearly with precursor cycling, with growth per cycle values of approximate to 0.1 nm/cycle. As-deposited films are smooth and contain nitrogen and carbon impurities attributed to poor ligand elimination from the Mo source. Upon high-temperature annealing, a large portion of the impurities are removed, and the authors obtain few-layer crystalline 2H-MoS2 films.