Formation of amorphous aluminum oxide and gallium oxide on InP substrates by water vapor oxidation

Amorphous aluminum oxide layers have been successfully produced by oxidizing amorphous (Al, As) compounds using water vapor at temperatures as low as 300 degrees C. The amorphous (Al, As) was deposited on InP substrates by molecular beam epitaxy at low temperatures (similar to 100 degrees C), and was found to have 50% more As than crystalline AlAs. Auger electron spectroscopy depth profiles indicate a complete depletion of As in the amorphous aluminum oxide layer. However, complete removal of As in the amorphous (Ga, As) layer requires a minimum oxidation temperature higher than 300 degrees C. This method has extended the use of native oxides to lattice-mismatched heterostructures. (C) 1998 American Institute of Physics. [S0021-8979(98)03124-7].