A study of the transient current during the formation of titanium oxide nanodots by AFM anodic oxidation

We analyze transient current data during the formation of titanium oxide nanodots by AFM-tip-induced anodic oxidation with the aim of getting further understanding of local oxidation kinetics. The measured current waveforms show a transition between two distinct regimes, in agreement to what was previously known of the growth process, and their behavior is discussed with respect to the oxide growth rate and to the formation of the space charge. Furthermore, it is shown how the knowledge of the duration of the first transient regime can be exploited to optimize the application of pulsed bias voltages to obtain a substantial improvement in aspect ratio of growing oxides.