Patterned layer design for group III nitride layer growth

A light emitting device, comprising:

• a substrate having a patterned surface that includes a masking structure forming a periodic pattern, wherein the patterned surface includes a top surface having a root mean square roughness less than approximately 0.5 nanometers and a plurality of openings formed in the top surface, wherein each of the plurality of openings has a characteristic size between approximately 0.1 microns and approximately five microns and a depth of at least 0.2 microns;
• and
• a first layer directly on the substrate, wherein the first layer is a group III-nitride material having an aluminum concentration of at least seventy percent and having a thickness at least twice the characteristic size of the openings, the first layer including:
• a first sub-layer directly on the substrate, the first sub-layer including a top patterned surface including a plurality of stress reducing regions;
• and
• a second sub-layer grown directly on the top patterned surface of the first sub-layer.

A device, comprising:

• a substrate having a patterned surface, wherein the patterned surface includes a top surface having a root mean square roughness less than approximately 0.5 nanometers and a plurality of openings in the top surface, wherein each of the plurality of openings has a characteristic size between approximately 0.1 microns and approximately five microns and a depth of at least 0.2 microns;
• and
• a buffer layer directly on the patterned surface of the substrate, wherein the buffer layer is a group III-nitride material having an aluminum concentration of at least seventy percent and having a thickness at least twice the characteristic size of the openings, wherein the buffer layer includes:
• a first sub-layer directly on the patterned surface of the substrate layer, wherein the first sub-layer has a substantially flat top surface with a root mean square roughness less than approximately 0.5 nanometers and a first plurality of stress reducing regions;
• a second sub-layer directly on the top surface of the first sub-layer, wherein the second sub-layer has a substantially flat top surface with a root mean square roughness less than approximately 0.5 nanometers and a second plurality of stress reducing regions;
• and
• a third sub-layer directly on the top surface of the second sub-layer, and wherein each of the plurality of first and second stress reducing regions and the plurality of openings forms a lateral hexagonal arrangement and wherein the top surfaces are close-packed along a vertical direction to form an overall hexagonal close-packed three dimensional structure.