Embodiments relate to applying a magnetic field across the paths of injected polar precursor molecules to cause spiral movement of the precursor molecules relative to the surface of a substrate. When the polar precursor molecules arrive at the surface of the substrate, the polar precursor molecules make lateral movements on the surface due to their inertia. Such lateral movements of the polar precursor molecules increase the chance that the molecules would find and settle at sites (e.g., nucleation sites, broken bonds and stepped surface locations) or react on the surface of the substrate. Due to the increased chance of absorption or reaction of the polar precursor molecules, the injection time or injection iterations may be reduced.