Kinetics of scanned probe oxidation: Space-charge limited growth

This article proposes an enhanced oxidation model for scanning probe micros cope (SPM) nanolithography that reproduces the power-of-time law reported f or tip-induced anodic oxidation. It is shown that the space charge resultin g from nonstoichiometric states strongly limits the oxidation rate. The dir ect relationship between the oxide thickness and time is provided by integr ation of the oxide rate equation. Measurements on SPM-induced oxides genera ted on a titanium surface are compared to theory. The predominant role of t he space charge is corroborated by electrical measurements on oxide barrier s that exhibit current fluctuations due to Coulombic effects. (C) 2000 Amer ican Institute of Physics. [S0021-8979(00)04310-3].