FAST RECOVERY SWITCHING DIODE WITH CARRIER STORAGE AREA

摘要

A power device (such as a power diode) has a peripheral die area and a central area. The main PN junction of the device is formed by a P+ type region that extends down into an N− type layer. The central portion of the P+ type region has a plurality of openings so mesa structures of the underlying N− type material extend up to the semiconductor surface through the openings. Due to the mesa structures being located in the central portion of the die, there are vertically extending extensions of the PN junction in the central portion of the die. Minority carrier charge storage is more uniform per unit area across the surface of the die. Due to the form of the P+ type region and the mesa structures, the reverse recovery of the PN junction exhibits a soft characteristic.

主权项

1. A power diode semiconductor die comprising:
a first layer of N+ type semiconductor material; a metal cathode electrode disposed underneath the first layer; a second layer of N− type semiconductor material disposed over the first layer, wherein the second layer has an upper surface that extends in a plane; a P+ type region of P+ type semiconductor material, wherein the P+ type region extends down from the plane into the second layer such that N− type semiconductor material of the second layer laterally surrounds the P+ type region in a ring, wherein the ring of the N− type semiconductor material extends up to the plane, and wherein the P+ type region is formed such that a plurality of N− type mesas of the N− type semiconductor material of the second layer extend up to the plane within the ring so that each N− type mesa is laterally surrounded at the plane by a ring of the P+ type semiconductor material of the P+ type region; a plurality of features of an insulation layer, where each respective one of the plurality of N− type mesas is covered by a corresponding respective one of the plurality of features; and a metal anode electrode disposed over the P+ type region such that the plurality of features of the insulation layer separate the N− type mesas from the metal anode electrode, wherein the power diode semiconductor die is operable as a high voltage power diode to conduct a forward current from the metal anode electrode, through the P+ type region, and to the metal cathode electrode.