Molybdenum disulfide (MoS 2 ) thin films were grown directly on SiO 2 covered wafers by atomic layer deposition (ALD) at the deposition temperatures ranging from 175 to 225 °C using molybdenum hexacarbonyl [Mo(CO) 6 ] and H 2 S plasma as the precursor and reactant, respectively. Self-limited film growth on the thermally-grown SiO 2 substrate was observed with both the precursor and reactant pulsing time. The growth rate was ∼0.05 nm/cycle and a short incubation cycle of around 13 was observed at a deposition temperature of 175 °C. The MoS 2 films formed nanocrystalline microstructure with a hexagonal crystal system (2H-MoS 2 ), which was confirmed by X-ray diffraction and transmission electron microscopy. Single crystal MoS 2 nanosheets, ∼20 nm in size, were fabricated by controlling the number of ALD cycles. The ALD-MoS 2 thin films exhibited good stoichiometry with negligible C impurities, approximately 0.1 at.% from Rutherford backscattering spectrometry (RBS). X-ray photoelectron spectroscopy confirmed the formation of chemical bonding from MoS 2 . The step coverage of ALD-MoS 2 was approximately 75% at a 100 nm sized trench. Overall, the ALD-MoS 2 process made uniform deposition possible on the wafer-scale (4 in. in diameter).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films