| 摘要 |
PURPOSE:To obtain a quality insulating film with a small surface level density through a process consisting of, when an oxide film is formed on a GaAs substrare, prebiously, providing an additional layer of thin metallic-As film or a low-class As oxide layer and feeding an As component to the substrate in substrate heat-oxidation process. CONSTITUTION:A thin metallic-As film 2 is vacuum-deposited or As is deposited in the low vacuum whose O2 pressure is set to 10<-4>-10<-3> Torr on the surface of a GaAs substrate 1. A thin low-class oxide film 2 is deposited thereon. Next, thus- obtained work is heat-treated in O2 gas or the mixture gas of O2 and N2 through two-step reaction. Namely, in the first step, the film 2 is oxidized to generate a quality As2O3 layer at the atmospheric temperatures of 230-350 deg.C and, in the second step, the base material of the substrate 1 is oxidized using the As2O3 film as protective film. Thereby, the Ga2O3 layer generated on the base material by the As2O3 layer generated at the surface of the substrate 1 is prevented to transfer for obtaining an insulating film with an As2O3/Ga2O3 ratio of 1. |
