Vertical GaN power device with breakdown voltage control
View Patent ↗A method for fabricating a vertical GaN power device includes providing a first GaN material having a first conductivity type and forming a second GaN material having a second conductivity type and coupled to the first GaN material to create a junction. The method further includes implanting ions through the second GaN material and into a first portion of the first GaN material to increase a doping concentration of the first conductivity type. The first portion of the junction is characterized by a reduced breakdown voltage relative to a breakdown voltage of a second portion of the junction.
1. A vertical GaN power device comprising:
a first GaN material having a first conductivity type;
a second GaN material having a second conductivity type and coupled to the first GaN material to form a p-n junction; and
an implanted region extending from within the first GaN material across the p-n junction into the second GaN material, wherein the implanted region spans a first portion of the p-n junction, such that the p-n junction extends from within the implanted region across a boundary of the implanted region into a second portion of the p-n junction,
wherein the first portion of the p-n junction has a breakdown voltage which is less than a breakdown voltage of the second portion of the p-n junction.
2. The device of claim 1 the second portion of the junction is disposed between an edge of the junction and the first portion of the junction.
3. The device of claim 1 wherein the first conductivity type comprises an n-type conductivity.
4. The device of claim 3 wherein the implanted region comprises silicon.
5. The device of claim 1 wherein the first portion of the junction forms part of a device region.
6. The device of claim 1 wherein the device comprises a diode.
7. The device of claim 6 wherein the diode comprises a Schottky barrier diode.
8. The device of claim 1 further comprising one or more edge termination structures.
9. A vertical III-nitride power device comprising:
a p-n junction formed by a first GaN material of a first conductivity type coupled to a second GaN material of a second conductivity type, wherein the junction further includes:
a device region; and
a controlled breakdown region within the device region, wherein the controlled breakdown region extends from within the first GaN material across a boundary between the first and second GaN materials into the second GaN material, wherein the controlled breakdown region spans a first portion of the junction in the device region, such that the junction extends from within the controlled breakdown region across a boundary of the controlled breakdown region into a second portion of the junction, and wherein the junction in the controlled breakdown region is characterized by having a lower breakdown voltage than at least a portion of the device region outside of the controlled breakdown region.
10. The device of claim 9 further comprising an edge-termination region adjacent to the device region and having one or more edge-termination structures.
11. The device of claim 9 wherein a first dopant concentration of the first GaN material in the controlled breakdown region is higher than a second dopant concentration of the first GaN material in the portion of the device region outside of the controlled breakdown region.