Schottky barrier diode
AssigneeTDK Corporation
InventorsJun Arima, Minoru Fujita, Katsumi Kawasaki, Jun Hirabayashi
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Abstract
To prevent dielectric breakdown of a Schottky barrier diode using gallium oxide. A Schottky barrier diode has a drift layer provided on a semiconductor substrate, an anode electrode, and a cathode electrode. A width W1 of an outer peripheral trench formed in the drift layer is larger than a width W2 of a center trench. An outer peripheral wall S1 of the outer peripheral trench is curved so as to approach vertical toward the outside, while an inner peripheral wall S2 thereof is closer to vertical than the outer peripheral wall S1. This relaxes an electric field which occurs at the outer peripheral bottom portion of the outer peripheral trench upon application of a backward voltage.
Claims5
A Schottky barrier diode comprising:
- a semiconductor substrate made of gallium oxide;
- a drift layer made of gallium oxide and provided on the semiconductor substrate;
- an anode electrode brought into Schottky contact with the drift layer;
- a cathode electrode brought into ohmic contact with the semiconductor substrate;
- and
- a first insulating film covering an inner wall of a trench formed in the drift layer,
- wherein the trench includes a ring-shaped outer peripheral trench and a center trench formed in an area surrounded by the outer peripheral trench,
- wherein a part of the anode electrode is embedded in the outer peripheral trench and the center trench through the first insulating film,
- wherein the outer peripheral trench is larger in width than the center trench,
- wherein the outer peripheral trench includes an outer peripheral wall surface and an inner peripheral wall surface being closer to the center trench than the outer peripheral wall surface,
- wherein, in a cross-sectional view, a first portion of the outer peripheral wall surface and a second portion of the inner peripheral wall surface each extend from an opening of the outer peripheral trench to a first depth measured from the opening in a thickness direction of the semiconductor substrate,
- wherein, in the cross-sectional view, the first portion of the outer peripheral wall surface has a curved surface having a curvature that becomes smaller from the first depth toward the opening of the outer peripheral trench, and
- wherein the second portion of the inner peripheral wall surface of the outer peripheral trench is less curved than the first portion of the outer peripheral wall surface.
Dependencies are inferred from the claim text.