| 摘要 |
PURPOSE:To change a low resistance layer and a high resistance region into travelling regions conforming to the desired frequency by a method wherein the high resistance region is formed adjoining to a tunnel injection region made up by the low resistance layer, and the high resistance region is turned into a depletion layer together with the tunnel injection region during operation. CONSTITUTION:A nu(n) type layer 11 with comparatively high resistance is built up on an n<+> semiconductor substrate 10. With an n<+> low resistance layer 12, a tunnel injection region, its thickness is 0.2mum or lower, its impurity concentration is higher than the nu(n) high resistance layer 11 and its effective donor density is 1X10<17>cm<-3> or more. A p<+> low resistance layer 13 is a p<+> layer having impurity density at least several times as much as the n<+> low resistance layer 12. The n<+> low resistance layer 12 and nu(n) high resistance layer 11 are changed into depletion layers when biased in the reverse direction, and the thickness of both layers 11, 12 is determined so that the total of the thickness becomes approximate desired oscillation frequency. |
