Characterization of epitaxial GaAs and Al_xGa_1-xAs layers doped with oxygen

Abstract

Intentional oxygen doping (≳1017 cm-3) of GaAs and Al0.30Ga0.70As epitaxial layers was achieved during metalorganic vapor phase epitaxy through use of an oxygen-bearing metalorganic precursor, dimethylaluminum methoxide (CH3)2AlOCH 3. The incorporation of oxygen and very low levels of Al (AlAs mole fraction <0.005) in the GaAs layers leads to the compensation of intentionally introduced Si donors. Additionally, deep levels in GaAs associated with oxygen were detected. The introduction of dimethyl aluminum methoxide during AlxGa1-xAs growth did not alter Al mode fraction or degrade the crystallinity of the ternary layers, but did incorporate high levels of oxygen which compensated Si donors. The compensation in both GaAs and Al0.30Ga0.70As indicates that high resistivity buffer layers can be grown by oxygen doping during metalorganic vapor phase epitaxy.