NANOSCALE ETCHING OF GAAS-SURFACES IN ELECTROLYTIC SOLUTIONS BY HOLE INJECTION FROM A SCANNING TUNNELING MICROSCOPE TIP

Controllable etching of GaAs(100) has been electrochemically achieved on a nanometer scale by using a scanning tunneling microscope (STM) in acidic solutions (pH=2-3). The realized features on n-GaAs(100) surfa ce were as small as 10 nm. We studied the dependence of the etching ra te on the potentials applied to the STM tip as well as the GaAs substr ate. These results indicate that the hole injection from the tip is re sponsible for the local etching of GaAs surfaces in electrolytes rathe r than local charges induced by an electric field. (C) 1997 American V acuum Society. [S0734-211X(97)04205-4].