Epitaxial devices
Epitaxial growth methods and devices are described that include a textured surface on a substrate. Geometry of the textured surface provides a reduced lattice mismatch between an epitaxial material and the substrate. Devices formed by the methods described exhibit better interfacial adhesion and lower defect density than devices formed without texture. Silicon substrates are shown with gallium nitride epitaxial growth and devices such as LEDs are formed within the gallium nitride.
1. A light emitting diode, comprising:
a silicon substrate;
one or more angled surfaces formed on the silicon substrate;
epitaxial gallium nitride formed on the one or more angled surfaces; and
a P-N junction located in the epitaxial gallium nitride to provide light as electrons combine with holes across the P-N junction.
2. The light emitting diode of claim 1 , wherein the one or more angled surfaces includes an array of angled surfaces.
3. The light emitting diode of claim 1 , wherein the one or more angled surfaces are asymmetric.
4. The light emitting diode of claim 2 , wherein the array of angled surfaces are included in an array of pyramid shaped structures.
5. The light emitting diode of claim 2 , wherein the array of angled surfaces are included in an array of conical shaped structures.
6. The light emitting diode of claim 1 , wherein the one or more angled surfaces are positioned between approximately 10 and 15 degrees with respect to a surface plane of the substrate.
7. A light emitting diode, comprising:
a silicon substrate;
one or more angled surfaces formed on the silicon substrate;
epitaxial gallium arsenide formed on the one or more angled surfaces; and
a P-N junction located in the epitaxial gallium arsenide to provide light as electrons combine with holes across the P-N junction.
8. The light emitting diode of claim 7 , wherein the one or more angled surfaces includes a number of periodically repeating angled surfaces with a surface normal vector that is between 0 degrees and 90 degrees with respect to a plane of the surface of the substrate.
9. The light emitting diode of claim 7 , wherein the one or more angled surfaces includes a number of linear structures.
10. The light emitting diode of claim 9 , wherein the one or more angled surfaces are asymmetric.
11. The light emitting diode of claim 7 , wherein the one or more angled surfaces are included in an array of pyramid shaped structures.
12. The light emitting diode of claim 7 , wherein the one or more angled surfaces are included in an array of conical shaped structures.
13. The light emitting diode of claim 7 , wherein the one or more angled surfaces are positioned between approximately 10 and 15 degrees with respect to a surface plane of the substrate.
14. A light emitting diode, comprising:
a silicon substrate;
one or more angled surfaces formed on the silicon substrate;
epitaxial gallium antimonide formed on the one or more angled surfaces; and
a P-N junction located in the epitaxial gallium antimonide to provide light as electrons combine with holes across the P-N junction.
15. The light emitting diode of claim 12 , wherein the one or more angled surfaces includes an array of island texture features.
16. The light emitting diode of claim 13 , wherein the array of island texture features includes angled surfaces that are asymmetric.
17. The light emitting diode of claim 13 , wherein the array of island texture features includes pyramid shaped structures.
18. The light emitting diode of claim 13 , wherein the array of island texture features includes conical shaped structures.
19. The light emitting diode of claim 1 , wherein the one or more angled surfaces are positioned between approximately 10 and 15 degrees with respect to a surface plane of the substrate.
20. A light emitting diode, comprising:
a silicon substrate;
one or more angled surfaces formed on the silicon substrate;
an epitaxial material formed on the one or more angled surfaces, the epitaxial material having a lattice constant that is different from the substrate; and
a P-N junction located in the epitaxial material to provide light as electrons combine with holes across the P-N junction.