Gallium nitride transistor having a source/drain structure including a single-crystal portion abutting a 2D electron gas
The present description relates to a gallium nitride transistor which includes at least one source/drain structure having low contact resistance between a 2D electron gas of the gallium nitride transistor and the source/drain structure. The low contact resistance may be a result of at least a portion of the source/drain structure being a single-crystal structure abutting the 2D electron gas. In one embodiment, the single-crystal structure is grown with a portion of a charge inducing layer of the gallium nitride transistor acting as a nucleation site.
1. A microelectronic structure comprising:
a gallium nitride layer;
a charge inducing layer on the gallium nitride layer;
a 2D electron gas within the gallium nitride layer; and
a source/drain structure including a single-crystal portion abutting the 2D electron gas;
wherein the single-crystal portion is indium gallium nitride having a crystal orientation aligned substantially parallel to m-planes of a hexagonal wurtzite crystal structure of the gallium nitride layer.
2. The microelectronic structure of claim 1 , wherein the single-crystal portion of the source/drain structure is N+ doped.
3. A microelectronic structure comprising:
a gallium nitride layer;
a charge inducing layer on the gallium nitride layer;
a 2D electron gas within the gallium nitride layer; and
a source/drain structure including a single-crystal portion abutting the 2D electron gas;
wherein the single-crystal portion is gallium nitride having a crystal orientation aligned substantially parallel to m-planes of a hexagonal wurtzite crystal structure of the gallium nitride layer.
4. The microelectronic structure of claim 3 , wherein the single-crystal portion of the source/drain structure is N+ doped.
5. A microelectronic structure comprising:
a gallium nitride layer;
a charge inducing layer on the gallium nitride layer;
a 2D electron gas within the gallium nitride layer; and
a source/drain structure including a single-crystal portion abutting the 2D electron gas;
wherein the charge inducing layer comprises a polarization layer formed on a crystal transition layer, wherein the crystal transition layer abuts the gallium nitride layer.
6. The microelectronic structure of claim 5 , wherein the polarization layer comprises aluminum indium nitride.
7. The microelectronic structure of claim 5 , wherein the crystal transition layer comprises indium nitride.
8. The microelectronic structure of claim 5 , wherein the crystal transition layer comprises aluminum nitride.
9. A microelectronic structure comprising:
a gallium nitride layer;
a charge inducing layer on the gallium nitride layer;
a 2D electron gas within the gallium nitride layer;
a source/drain structure including a single-crystal portion abutting the 2D electron gas; and
a poly crystal portion of the source/drain structure abutting the single-crystal portion of the source/drain structure and the gallium nitride layer.
10. An electronic system, comprising:
a board; and
a microelectronic device attached to the board, wherein the microelectronic device includes at least one gallium nitride transistor comprising a gallium nitride layer, a charge inducing layer on the gallium nitride layer, a 2D electron gas within the gallium nitride layer, and a source/drain structure including a single-crystal portion abutting the 2D electron gas, wherein the single-crystal portion is indium gallium nitride having a crystal orientation aligned substantially parallel to m-planes of a hexagonal wurtzite crystal structure of the gallium nitride layer.
11. The electronic system of claim 10 , wherein the single-crystal portion of the source/drain structure is N+ doped.
12. An electronic system comprising:
a board; and
a microelectronic device attached to the board, wherein the microelectronic device includes at least one gallium nitride transistor comprising a gallium nitride layer, a charge inducing layer on the gallium nitride layer, a 2D electron gas within the gallium nitride layer, and a source/drain structure including a single-crystal portion abutting the 2D electron gas, wherein the single-crystal portion is gallium nitride having a crystal orientation aligned substantially parallel to m-planes of a hexagonal wurtzite crystal structure of the gallium nitride layer.
13. The electronic system of claim 12 , wherein the single-crystal portion of the source/drain structure is N+ doped.
14. An electronic system comprising:
a board; and
a microelectronic device attached to the board, wherein the microelectronic device includes at least one gallium nitride transistor comprising a gallium nitride layer, a charge inducing layer on the gallium nitride layer, a 2D electron gas within the gallium nitride layer, and a source/drain structure including a single-crystal portion abutting the 2D electron gas, wherein the charge inducing layer comprises a polarization layer formed on a crystal transition layer, wherein the crystal transition layer abuts the gallium nitride layer.
15. The electronic system of claim 14 , wherein the polarization layer comprises aluminum indium nitride.
16. The electronic system of claim 14 , wherein the crystal transition layer comprises indium nitride.
17. The electronic system of claim 14 , wherein the crystal transition layer comprises aluminum nitride.
18. An electronic system comprising:
a board; and
a microelectronic device attached to the board, wherein the microelectronic device includes at least one gallium nitride transistor comprising a gallium nitride layer, a charge inducing layer on the gallium nitride layer, a 2D electron gas within the gallium nitride layer, a source/drain structure including a single-crystal portion abutting the 2D electron gas, and a poly-crystal portion of the source/drain structure abutting the single-crystal portion of the source/drain structure and the gallium nitride layer.