Photoinduced oxide film formation on n-type GaN surfaces using alkaline solutions

We report on photoassisted wet chemical formation of thin oxide films on n- GaN layers in potassium hydroxide based electrolytes at room temperature. T he kinetics of the oxide formation and dissolution were examined via photoc urrent transients. The tendency of the photocurrent to level out during pho toelectrochemical etching experiments is associated with a quasiequilibrium state at the semiconductor/electrolyte interface. Homogeneous oxide films were grown in weak alkaline solutions (11 < pH < 13) under potentionstatic control with oxidation rates of up to 250 nm/h and characterized by Auger e lectron spectroscopy. Consequences on wet photochemical etch strategies are discussed. (C) 2000 American Institute of Physics. [S0003-6951(00)00826-3] .