SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a semiconductor device capable of achieving a high oscillation resistance.SOLUTION: A p-type base layer 2 is provided on an upper surface of an n-type drift layer 1. An n-type emitter layer 8 is provided partially on the p-type base layer 2. A trench gate 10 is provided so as to penetrate through the n-type emitter layer 8 and the p-type base layer 2. A p-type collector layer 12 is provided on a lower surface of the n-type drift layer 1. An n-type buffer layer 4 is provided between the n-type drift layer 1 and the p-type collector layer 12. A peak concentration of the n-type buffer layer 4 is higher than that of the n-type drift layer 1 and lower than that of the p-type collector layer 12. A carrier concentration of the n-type buffer layer 4 is increased from the n-type drift layer 1 side toward the p-type collector layer 12 side by an exponential function of a depth. An inclination of the carrier concentration of the n-type buffer layer 4 at a connection part between the n-type drift layer 1 and the n-type buffer layer 4 is 20-2000 cm.SELECTED DRAWING: Figure 6