| 摘要 |
PURPOSE:To obtain a thermally stable wafer, which has high mobility and characteristics thereof do not change before and after the projection of beams, by growing a GaAs layer on a substrate, growing a superlattice consisting of AlGaAs of two kinds and growing AlxGa1-xGa (x<=0.2) containing an N-type impurity in high concentration. CONSTITUTION:Epitaxial layers 2-5 grown through molecular-beam epitaxy are formed onto a semi-insulating (100) GaAs substrate 1. The layer 2 consists of an undoped GaAs layer of 1mum thickness, the layer 3 has superlattice struc ture, and layer 31 are composed of Al0.45Ga0.55As and layers 32 GaAs (each thickness of 20Angstrom ). The layers 31 and 32 are used as one period and superposed at five periods in the superlattice structure 3. The electron supply layer 4 consists of AlxGa1-xAs (x=0.2) in 300Angstrom to which Si of 1X10<17>cm<-3> is doped, and the cap layer 5 is composed of an undoped GaAs layer (200Angstrom ).
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