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:
an epitaxially grown binary gallium compound having a first surface and a second surface that is opposite and substantially parallel to the first surface;
one or more angled features formed in the first surface, wherein the angled features are angled with respect to the second surface; and
a P-N junction located in the epitaxially grown binary gallium compound to provide light as electrons combine with holes across the P-N junction.
2. The light emitting diode of claim 1 , wherein the epitaxially grown binary gallium compound is gallium nitride.
3. The light emitting diode of claim 1 , wherein the epitaxially grown binary gallium compound is gallium arsenide.
4. The light emitting diode of claim 1 , wherein the epitaxially grown binary gallium compound is gallium antimonide.
5. The light emitting diode of claim 1 , wherein the one or more angled features includes an array of angled features.
6. The light emitting diode of claim 5 , wherein the array of angled features are included in an array of pyramid shaped features.
7. The light emitting diode of claim 1 , wherein the one or more angled features are asymmetric.
8. A light emitting diode, comprising:
an epitaxially grown gallium nitride material having a first surface and a second surface that is opposite and substantially parallel to the first surface;
one or more angled features formed in the first surface, wherein the angled features are angled with respect to the second surface; and
a P-N junction located in the epitaxially grown gallium nitride material to provide light as electrons combine with holes across the P-N junction.
9. The light emitting diode of claim 8 , wherein the one or more angled features includes an array of angled features.
10. The light emitting diode of claim 9 , wherein the array of angled features are included in an array of pyramid shaped features.
11. The light emitting diode of claim 9 , wherein the array of angled features are included in an array of conical shaped structures.
12. The light emitting diode of claim 8 , wherein the one or more angled features are asymmetric.
13. The light emitting diode of claim 1 , wherein the one or more angled features are angled between approximately 10 and 15 degrees with respect to the second surface.
14. A light emitting diode, comprising:
an epitaxially grown gallium nitride material having a first surface and a second surface that is opposite and substantially parallel to the first surface;
one or more angled features formed in the first surface, wherein the angled features each have an angled surface defining an angle with respect to the second surface;
wherein a lattice spacing of the gallium nitride material along the angled surface substantially corresponds to a modified lattice spacing of silicon at the angle; and
a P-N junction located in the epitaxially grown gallium nitride material to provide light as electrons combine with holes across the P-N junction.
15. The light emitting diode of claim 14 , wherein the angled surfaces include a number of periodically repeating angled surfaces wherein each angle is between 0 degrees and 90 degrees with respect to the second surface.
16. The light emitting diode of claim 15 , wherein the angled surfaces include a number of periodically repeating angled surfaces wherein each angle is between 10 degrees and 15 degrees with respect to the second surface.
17. The light emitting diode of claim 14 , wherein the one or more angled surfaces are included in a number of linear features.