Vertical GaN JFET with low gate-drain capacitance and high gate-source capacitance
View Patent ↗An embodiment of a vertical power device includes a III-nitride substrate, a drift region coupled to the III-nitride substrate and comprising a III-nitride material of a first conductivity type, and a channel region coupled to the drift region and comprising a III-nitride material of the first conductivity type. The vertical power device also includes a source region coupled to the channel region and comprising a III-nitride material of the first conductivity type, and a gate region coupled to the channel region. The gate region includes a III-nitride material of a second conductivity type. The vertical power device further includes a source-coupled region coupled to the drift region and electrically connected with the source region. The source-coupled region includes a III-nitride material of the second conductivity type.
1. A vertical power device comprising:
a III-nitride substrate;
a III-nitride drift region coupled to the III-nitride substrate and having a first conductivity type;
a III-nitride channel region coupled to the III-nitride drift region and having the first conductivity type;
a III-nitride source region coupled to the III-nitride channel region and having the first conductivity type;
a III-nitride gate region coupled to the III-nitride channel region, wherein the III-nitride gate region has a second conductivity type; and
a source-coupled region coupled to the III-nitride drift region and electrically connected with the III-nitride source region, wherein the source-coupled region comprises a III-nitride material of the second conductivity type.
2. The vertical power device of claim 1 wherein an area defined by a junction of the III-nitride gate region and the III-nitride drift region is smaller than an area defined by a junction of the source-coupled region and the III-nitride drift region.
3. The vertical power device of claim 1 further comprising forming an edge termination structure.
4. The vertical power device of claim 3 wherein the edge termination structure surrounds at least the III-nitride source region, the III-nitride channel region, the source-coupled region, and the III-nitride gate region.
5. The vertical power device of claim 1 wherein:
the III-nitride channel region is one of a plurality of channel regions; and
the III-nitride gate region is coupled to and completely surrounds each of the plurality of channel regions.
6. The vertical power device of claim 1 wherein least one metal layer electrically connects the source-coupled region to the III-nitride source region.
7. The vertical power device of claim 1 further comprising a gap separating the III-nitride channel region from the source-coupled region, wherein a width of the gap is smaller than a width of the III-nitride channel region.
8. The vertical power device of claim 1 further comprising an overlap area, the overlap area comprising a dielectric layer disposed between at least a portion of the source-coupled region and at least a portion of a gate electrode electrically connected with the III-nitride gate region.