Power semiconductor devices with mesa structures and buffer layers including mesa steps

摘要

bipolar junction transistor is a collector having a first conductivity type , the first conductivity type on the collector having the drift layer , the first conductive type and the second base layer on the drift layer having a conductivity type opposite the first conductivity type having a base on the floor , which forms the base layer and the pn junction lightly doped buffer layer , and having the first conductivity type on the buffer layer , and an emitter mesa having a side wall . The buffer layer includes a mesa step that is laterally spaced to the adjacent side wall of the emitter mesa , the first thickness of the buffer layer of the emitter mesa bottom is greater than the second thickness of the buffer layer outside the mesa step of . ;