| 摘要 |
PURPOSE:To form semiconductor layers containing an impurity in hole parts only easily by a method wherein a compound semiconductor substrate is etched through apertures formed in a heat resistant dielectric film to form the holes. CONSTITUTION:Compound semiconductor layers 12-16 are successively formed on a semi-insulating GaAs substrate 11 by epitaxial crystal growth. After that, SiO2 is deposited on the substrate surface and holes are drilled in the parts where semi-insulating buried layers 17 are to be formed and semi-insulating GaAs containing a dopant which gives GaAs semi-insulating property is made to grow selectively. The selective growth of N-type GaAs progresses so as to refill the holes and the growth is discontinued when the surface becomes almost flat. At that time, GaAs hardly or incompletely adheres to the remaining SiO2 film and, after the growth, GaAs on the remaining SiO2 film is removed simultaneously when the SiO2 film is removed. Therefore, the buried layers for element isolation can be formed easily and a transistor which has a flat top surface can be formed.
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