The deposition rate and properties of MLD films are for a large part determined by what happens during the reactant exposure step. In some cases, however, the purge step is...

A facile low temperature co-precipitation method for the synthesis of crystalline cobalt ferrite nanostructures using ferrous sulfate salt as the precursor has been discussed. The prepared samples were compared with nanoparticles prepared by conventional co-precipitation and hydrothermal methods using ferric nitrate as the precursor. X-ray diffraction studies confirmed the formation of cubic spinel cobalt ferrites when dried at 110 °C as opposed to conventional methods which required higher temperatures/pressure for the formation of the same. Field emission scanning electron microscope studies of these powders revealed the formation of nearly spherical nanostructures in the size range of 20-30 nm which were comparable to those prepared by conventional methods. Magnetic measurements confirmed the ferromagnetic nature of the cobalt ferrites with low magnetic remanance. Further magnetic hyperthermia studies of nanostructures prepared by low temperature method showed a rise in temperature to 50 °C in 600 s.

Infiltration of trimethylaluminum (TMA) in molecular layer deposition-enabled alucone thin films on planar substrates is a common observation reported in the literature. An insufficient TMA purge time in such cases is often found to lead to a CVD component in the overall film growth due to the reactions between the outgassing TMA and the co-reactant. In this work, the effect of the CVD component on the step coverage of alucone films when grown in high-aspect ratio trenches is studied. The thickness was initially found to increase with increasing distance from the trench aperture before starting to decrease up to the film’s maximum penetration depth. With the support of modeling, the reason behind the observed thickness profile was investigated and attributed to the combination of an increasing outgassing rate of TMA and a decreasing ethylene glycol (EG) concentration along the trench depth. Furthermore, the maximum thickness and the position where it is obtained in the trench are found to depend on TMA and EG doses, TMA purge time, the trench height, and the trench depth. Finally, the possibility of adopting the additional CVD component in film growth for void-less gap fill of 3D trenches is discussed, as well as the suppression of the same CVD component, without compromising the growth rate, by using dimethylaluminum isopropoxide as a substitute for TMA is evaluated.