SUPER-JUNCTION MOSFET, MANUFACTURING METHOD THEREFOR, AND COMPOSITE SEMICONDUCTOR DEVICE WITH PARALLEL CONNECTED DIODES

摘要

PROBLEM TO BE SOLVED: To provide a super-junction MOSFET capable of reducing a reverse recovery current (Irp) and a reverse recovery time (trr) by moderating a hard recovery waveform at the time of reverse recovery operation, thereby making it possible to obtain high-speed switching and reduce a reverse recovery loss.;SOLUTION: Provided is a super-junction MOSFET having, on a first main surface of an n-type semiconductor substrate 1, a plurality of pn junctions 6 parallel to each other and extending in the vertical direction, a parallel pn layer 4 in which an n-type drift region 4a and a p-type partition region 4b sandwiched between the pn junctions 6 are juxtaposed adjacent to each other, and a MOS gate structure on the first main surface side of the parallel pn layer 4, an n-type first buffer layer 3 and second buffer layer 2 being in contact therewith in the order stated. The super-junction MOSFET is characterized in that the impurity concentration of the first buffer layer 3 is a low concentration about equal to or less than that of the n-type drift region 4a, the impurity concentration of the second buffer layer 2 is a higher concentration than that of the n-type drift region 4a, and the carrier life time of the n-type semiconductor substrate 1 on the first main surface side is made to be shorter than that of the second buffer layer 2.;COPYRIGHT: (C)2015,JPO&INPIT