| 摘要 |
PURPOSE:To effectively suppress impact ionization by a method wherein a transistor channel layer is so constituted that films high in electron migration rate in a weak electric field and films high in electron migration rate in a strong electric field are stacked one upon another alternately and periodically. CONSTITUTION:A channel layer is constituted of compound semiconductor thin films of one type and compound semiconductor thin films of the other type that are stacked one upon another periodically. Accordingly, in a chemical compound thin film, an energy gap may be produced so large that impact ionization is difficult to take place. lt is also possible for the probability of the presence of electrons made so high in the other type of compound semiconductor thin film that impact ionization will never take place. For example, a channel layer of this design may be a multi-film crystalline compound semiconductor layer 2 in which six approximately 60Angstrom thick InAs films and six approximately 100Angstrom -thick InP films may be stacked one upon another alternately.
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