Vertical III-nitride semiconductor device with a vertically formed two dimensional electron gas
A HEMT device comprising a III-Nitride material substrate, the surface of which follows a plane that is not parallel to the C-plane of the III-Nitride material; an epitaxial layer of III-Nitride material grown on said substrate; a recess etched in said epitaxial layer, having at least one plane wall parallel to a polar plane of the III-Nitride material; a carrier supply layer formed on a portion of the plane wall of the recess, such that a 2DEG region is formed along the portion of the plane wall of the recess; a doped source region formed at the surface of said epitaxial layer such that the doped source region is separated from said 2DEG region by a channel region of the epitaxial layer; a gate insulating layer formed on the channel region of the epitaxial layer; and a gate contact layer formed on the gate insulating layer.
1. A HEMT device comprising:
a III-Nitride material substrate, a surface of which follows a plane that is not parallel to the C-plane of the III-Nitride material;
an epitaxial layer of III-Nitride material grown on said substrate;
a recess etched in said epitaxial layer, the recess having at least one plane wall that is not parallel to the surface of the substrate; said at least one plane wall being parallel to a polar plane of the III-Nitride material;
at least one carrier supply layer formed on at least a portion of said at least one plane wall of the recess, such that a 2DEG region is formed along said at least a portion of said at least one plane wall of the recess;
a doped source region formed at the surface of said epitaxial layer such that the doped source region is separated from said 2DEG region by a channel region of the epitaxial layer, the source region extending parallel to the surface of the substrate up to said at least one plane wall of the recess;
a gate insulating layer formed on the channel region of the epitaxial layer; and
a gate contact layer formed on the gate insulating layer.
2. The HEMT device of claim 1 , wherein the gate contact layer is arranged in the recess along a portion of said at least one plane wall of the recess and the channel region extends parallel to the gate contact layer along said portion of said at least one plane wall of the recess.
3. The HEMT device of claim 2 , wherein said at least one carrier supply layer is formed on a portion of said at least one plane wall of the recess such that a further 2DEG region is formed along the channel region of the epitaxial layer.
4. The HEMT device of claim 1 , wherein said at least one plane wall of the recess is parallel to the C-plane of the III-Nitride material.
5. The HEMT device of claim 4 , wherein at least one plane wall of the recess is perpendicular to the surface of the substrate.
6. The HEMT device of claim 5 , wherein the surface of the substrate follows the M-plane of the III-Nitride material.
7. The HEMT device of claim 5 , wherein the surface of the substrate follows the A plane of the III-Nitride material.
8. The HEMT device of claim 1 , wherein the III-Nitride material substrate is a free standing III-Nitride material substrate.
9. The HEMT device of claim 1 , wherein the III-Nitride material is GaN.
10. The HEMT device of claim 1 , wherein the carrier supply layer comprises one of an epitaxial single crystal AlGaN, an epitaxial single crystal GaN/AlGaN and an epitaxial single crystal AlN.
11. The HEMT device of claim 1 , wherein the carrier supply layer comprises a spacer layer formed on the III-Nitride material epitaxial layer and a barrier layer formed on the spacer layer.
12. The HEMT device of claim 1 , wherein the carrier supply layer is grown on the III-Nitride material epitaxial layer such that the 2DEG region is formed in the epitaxial III-Nitride material along the surface of said at least a portion of said at least one plane wall of the recess.