| 摘要 |
PURPOSE:To produce a semiconductor device of high breakdown strength, driving large currents, and performing speedy operations by a method wherein a second semiconductor layer and a third semiconductor layer that is less in electron affinity and lower in impurity concentration are formed, in that order, on an n-type first semiconductor layer, and two ohmic regions are provided electrically connected to the first and second semiconductor layers. CONSTITUTION:A high-purity third semiconductor layer 15 just under a control electrode 18 decreases an electric field the portion just under the control electrode 18 may be exposed to and improve the electrode 18 in breakdown strength, as compared with a conventional design wherein a highly-doped layer is directly positioned just under the electrode 18. A high-concentration electron storage layer 21 under conditions where VG>VFB is valid is formed in a second semiconductor layer 14 for the generation in the channel of electrons Ne higher in concentration than impurity ND in an originally doped first semiconductor layer 13, for the output of greater currents. When VG>VFB is valid, the high-concentration electron layer 21 is formed in the second semiconductor layer 14, which realizes protection against ionized impurity scattering. This improves the rate of electron migration, which results in increased mutual conductance and currents.
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