LOW-VOLTAGE PUNCH-THROUGH BI-DIRECTIONAL TRANSIENT-VOLTAGE SUPPRESSION DEVICES AND METHODS OF MAKING THE SAME

摘要

A bi-directional transient voltage suppression device with symmetric current-voltage characteristics is provided. The device comprises: a lower semiconductor layer of first conductivity type (14); an upper semiconductor layer of first conductivity type (18); and a middle semiconductor layer (16) adjacent to and disposed between the lower and upper layers, the middle layer having a second conductivity type opposite the first conductivity type, such that upper and lower p-n junctions are formed. In this device, the middle layer has a net doping concentration that is highest at a midpoint between the junctions.