| 摘要 |
PURPOSE:To form an inverse hetero-junction which can be made to grow at high temperature and can be stable with respect to a heat treatment by a method wherein, when a nondoped GaAs layer is formed on an N-type AlxGa1-xAs layer, Si penetrates into the GaAs layer and the grown GaAs layer is vaporized in a high vacuum to expose the N-type AlxGa1-xAs layer and then a nondoped AlyGa1-yAs thin layer and a nondoped GaAs layer are made to grow. CONSTITUTION:After a nondoped GaAs layer 2 with about 0.1mum thickness and a nondoped Al0.3Ga0.7As layer 3 of about 0.2mum thickness are made to grow on a semi-insulating gaAs substrate 1 at the substrate temperature of 650 deg.C for instance, if an N-type Al0.3Ga0.7As layer 4 doped with Si with concentration of about 1X10<18>cm<-3> of 5oo Angstrom thickness and a nondoped GaAs layer 5 of 500Angstrom thickness are formed, Si penetrates into the layer 5. Then, if the substrate temperature is elevated to 720-750 deg.C while the Ga beam being discontinued, the layer 5 on the surface is vaporized and the layer 4 is exposed. Then, if the temperature is declined to the initial temperature of 630-650 deg.C and a nondoped Al0.3Ga0.7As layer 6 of about 100 Angstrom thickness and a GaAs layer 7 of about 1000Angstrom thickness are made to grow, Si hardly penetrates into the layer 7. Therefore, the purity of the GaAs layer is significantly improved and the mobility of two-dimensional electron gas accumulated in the hetero boundary of an inverse hetero-junction can be substantially improved.
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