Patent ID: 11876120
Assignee: NUVOTON TECHNOLOGY CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A semiconductor device comprising:
a substrate;
a channel layer disposed above the substrate, the channel layer being a group III nitride not containing Al;
a barrier layer disposed above the channel layer, the barrier layer being a group III nitride containing Al;
a gate electrode joined to the barrier layer;
a recess defined by removing at least a portion of the barrier layer from a surface of a laminated semiconductor including the channel layer and the barrier layer; and
an ohmic electrode disposed in the recess, the ohmic electrode being in ohmic contact with a two-dimensional electron gas layer generated in the channel layer, wherein
an Al composition ratio distribution of the barrier layer in a first direction perpendicular to a surface of the substrate has a maximum point at a first position,
the semiconductor device comprises, in the first direction:
a first inclined surface of the barrier layer, the first inclined surface including the first position and being in contact with the ohmic electrode; and
a second inclined surface of the barrier layer, the second inclined surface intersecting the first inclined surface at a first intersection line on a lower side of the first inclined surface and being in contact with the ohmic electrode,
an angle of the second inclined surface to the surface of the substrate is smaller than an angle of the first inclined surface to the surface of the substrate,
a second position that is a position of the first intersection line in the first direction is lower than the first position, and
in a plan view of the substrate:
the first intersection line includes three or more recess portions each being recessed toward a first inclined surface side in a second direction in which the first inclined surface and the second inclined surface are arranged; and
the three or more recess portions are irregularly arranged in a third direction that is an extending direction of the first intersection line.