SELECTIVE AREA EPITAXY OF GAAS USING GAAS OXIDE AS A MASK

The use of GaAs oxide as a mask material for in situ selective-area epitaxy of GaAs by metal organic molecular beam epitaxy (MOMBE) was studied. The GaAs oxide mask was patterned by electron-beam-induced chlorine etching. Using trimethylgallium (TMG) and As4as source materials, an epitaxial layer of GaAs was obtained on the opening of the GaAs oxide mask; no deposition was observed on the GaAs oxide. An observation of the thermal decomposition of TMG by mass spectrometry indicated that the thermal decomposition of TMG occurred above 350°C on an arsenic-stabilized surface, while decomposition did not occur below 550°C on the GaAs oxide surface. This surface-catalyzed reaction explains the selectivity of GaAs growth. © 1990 IOP Publishing Ltd.