Basic mechanisms of an atomic force microscope tip-induced nano-oxidation process of GaAs

An atomic force microscope (AFM) tip-induced direct nano-oxidation process of GaAs(100) substrates has been investigated, and is viewed as a promising method for the fabrication of nanometer-scale electronic devices such as single electron tunneling transistors. The effects of the AFM drawing parameters such as tip bias voltage and writing speed as well as the ambient humidity on the oxide line height and width were explored. The rate of reaction and its dependence on electric field strength and oxide thickness were examined to understand the basic mechanisms involved in the tip-induced oxidation of GaAs. The rate of oxidation/anodization was found to decrease rapidly with oxide film growth, which was explained at the simplest level in terms of a self-limiting influence of decreasing electric field strength. (C) 1998 American Institute of Physics.