Impurity concentration profile for semiconductor - low resistance base has low and high impurity concentration layers

摘要

The semiconductor has four or more layers and is formed from a monocrystalline element. The layers are alternate p and n types and a low resistance base has a low (11) and high (12) active impurity concentration layers. The low concentration layer contacts a high resistance base (2) at the side where its impurity concentration gradient is a minimum and its number of impurities is equal to the number in the high resistance base. The zone of the high concentration layer (12) where it contacts the emitter layer (3) has an impurity concentration at least one fiftieth the superficial impurity concentration of the emitter layer. The other side of high concentration layer has an impurity concentration gradient greater than 108 per cubic cm.