PHOTO-OXIDATION OF GAAS FOR INSITU PATTERNED-MASK FORMATION PRIOR TO CHLORINE GAS ETCHING

This is the demonstration of "in-situ masking" concept. In situ patterning of GaAs is carried out by using a photo-oxidized surface layer as a mask for subsequent Cl2 etching. Clean GaAs surface provided by molecular beam epitaxy is exposed to pure oxygen and is simultaneously irradiated with an Ar+ ion laser of the 514.5 nm line for photo-oxidation of the surface. Subsequent Cl2 gas etching of the photo-oxidized sample reveals that the GaAs oxide fills the role of an etching mask. The resistance of the oxide mask against Cl2 etching varies depending on the laser fluence with which the oxide of GaAs is formed.