A rotary reactor for thermal and plasma-enhanced atomic layer deposition on powders and small objects

To conformally coat large amounts of particles using atomic layer deposition (ALD), agitation of the particles and efficient reactant usage are necessary. A rotary reactor was developed to enable both thermal and plasma-enhanced ALD growth on agitated particles. The effectiveness of the rotary reactor design was demonstrated by depositing Al2O3, TiO2 and AlN by thermal and plasma-enhanced ALD on ZnO nanopowder, stainless steel micron sized powder, titanium granules and glass beads. In-situ optical emission spectroscopy (OES) and mass spectroscopy (MS) measurements were performed to monitor saturation of the ALD half reactions, while ex-situ X-ray fluorescence (XRF), X-ray photo-electron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) were used to confirm the composition and conformality of the deposited films.