Light emitting device substrate with inclined sidewalls

A method of fabricating a device, comprising:

• forming a device structure including a light emitting structure located on a first surface of a substrate, wherein the substrate includes a second surface parallel with the first surface, the second surface having a length that is less than a length of the first surface, the first surface extending horizontally underneath the light emitting structure beyond any borders of the light emitting structure with the substrate;
• forming a pair of opposing vertical side surfaces of the substrate, each extending vertically from an opposing end of the first surface, each of the opposing vertical side surfaces being perpendicular to one of the opposing ends of the first surface;
• forming a pair of opposing oblique sides of the substrate, each extending obliquely inward from one of the vertical side surfaces, each opposing oblique side extending obliquely inward to an opposing end of the second surface;
• and
• roughening the second surface of the substrate to improve an extraction of light through the second surface, wherein the roughened second surface includes a first roughening of a first scale and a second roughening of a second scale on the first roughening, wherein the first scale is an order of magnitude larger than a peak emission wavelength of light emitted by the light emitting structure and the second scale is on the order of the peak emission wavelength of the light emitted by the light emitting structure.

An ultraviolet light emitting device, comprising:

• an ultraviolet light emitting structure;
• and
• a sapphire substrate having a first surface with the ultraviolet light emitting structure located thereon and a second surface parallel with the first surface, the second surface having a length that is less than a length of the first surface, the first surface extending horizontally underneath the ultraviolet light emitting structure beyond any borders of the ultraviolet light emitting structure with the substrate, a pair of opposing vertical side surfaces each extending vertically from an opposing end of the first surface, each of the opposing vertical side surfaces being perpendicular to one of the opposing ends of the first surface, and a pair of opposing oblique sides each extending obliquely inward from one of the vertical side surfaces, each opposing oblique side extending obliquely inward to an opposing end of the second surface,
• wherein the second surface of the substrate is roughened to improve an extraction of light from the substrate, wherein the roughened second surface includes a first roughening of a first scale and a second roughening of a second scale on the first roughening, wherein the first scale is an order of magnitude larger than a peak emission wavelength of light emitted by the ultraviolet light emitting structure and the second scale is on the order of the peak emission wavelength of the light emitted by the ultraviolet light emitting structure.