US Patent No. 9,082,628

TRENCH SCHOTTKY DIODE


Patent No. 9,082,628
Issue Date July 14, 2015
Title Trench Schottky Diode
Inventorship Ning Qu, Reutlingen (DE)
Alfred Goerlach, Kusterdingen (DE)
Assignee ROBERT BOSCH GMBH, Stuttgart (DE)

Claim of US Patent No. 9,082,628

1. A trench Schottky diode, comprising:
a highly doped substrate of a first conductivity type;
an epitaxial layer of the first conductivity type and applied to the substrate, wherein:
the epitaxial layer includes at least two trenches,
the epitaxial layer is a stepped epitaxial layer including a first partial layer and a second partial layer of different doping
concentrations,

the first partial layer is contacted by the substrate and includes a higher doping concentration than the second partial layer,
the second partial layer is not contacted by the substrate,
the first partial layer determines a breakdown voltage of the trench Schottky diode, and
the trench Schottky diode is a trench Schottky barrier Schottky diode;
a first metal layer disposed at a rear side and serving as a cathode electrode;
a second metal layer disposed at a front side and extending into the trenches, the second metal layer serving as a control
electrode and forming a first Schottky contact with the second partial layer; and

a third metal layer disposed between the second metal layer and each of the bottoms of the trenches, the third metal layer
forming a second Schottky contact with the second partial layer and a third Schottky contact with the first partial layer
wherein a barrier height of the second Schottky contact is different from a barrier height of the third Schottky contact.