Contacts for an n-type gallium and nitrogen substrate for optical devices

A method for fabricating LED devices, the method comprising:

• providing a gallium and nitrogen containing substrate member comprising a backside surface and a front side surface, the front side surface including an n-type material overlying the substrate member, an active region overlying the n-type material, and a p-type material overlying the active region;
• subjecting the backside surface to a polishing process, causing a backside surface characterized by a surface roughness;
• subjecting the backside surface characterized by a surface roughness to an anisotropic etching process exposing various crystal planes to form a plurality of pyramid-like structures distributed spatially in a non-periodic manner on the backside surface, the plurality of pyramid-like structures characterizing a roughened region overlying a plane within a vicinity of the backside region, wherein the anisotropic etching process comprises use of a solution comprising silicic acid and potassium hydroxide;
• treating the backside surface, comprising a plurality of pyramid-like structures, to a plasma species to form a plasma-treated backside surface;
• subjecting the plasma-treated backside surface to a surface treatment to form a surface-treated backside;
• and
• forming a contact material comprising an aluminum bearing species or a titanium bearing species overlying the surface-treated backside to form a plurality of LED devices with the contact material such that the contact material forms an ohmic contact with the surface-treated backside of each of the plurality of LED devices.