Abstract: A method for fabricating an epitaxial structure includes providing a wafer comprising one or more epitaxial layers. The wafer is divided into dice where the area between the dice are called streets. Each street has a slot formed on either side of the street. The slots penetrate through the epitaxial layer but not the substrate leaving a portion of the epitaxial layer intact between the slots creating a “W” shaped cross section. A protective layer is then formed on the wafer. A laser may be used to singulate the wafer in to individual dice. The laser divides each street between the slots. The barrier walls of the epitaxial layers protect the individual dice from debris created by laser separation.

Abstract: The shape of a light emitting element 400;500) is designed to increase the amount of light that is able to escape from the surfaces of the light emitting element (400;500). The indices of refraction of the light emitting element (400;500) and the surrounding environment define an escape zone through which light may escape through a surface of the light emitting element (400;500). Light traveling outside the escape zone is totally internally reflected (TIR) at the surface. By increasing the number of surfaces on the light emitting element (400;500), the number of escape zones (410a-f,411a-f, 510a-h,511a-h) may be increased, with a corresponding increase in the likelihood of light escaping the surfaces. A light emitting element (400;500) comprising a polygonal surface area with more than four sides (402a-f;502a-h) exhibits a higher light extraction efficiency, and also allows a more uniform current injection, and experiences reduced mechanical stress, compared to one comprising a rectangular surface area.

Abstract: A method for fabricating an epitaxial structure includes providing a wafer comprising one or more epitaxial layers. The wafer is divided into dice where the area between the dice are called streets. Each street has a slot formed on either side of the street. The slots penetrate through the epitaxial layer but not the substrate leaving a portion of the epitaxial layer intact between the slots creating a “W” shaped cross section. A protective layer is then formed on the wafer. A laser may be used to singulate the wafer in to individual dice. The laser divides each street between the slots. The barrier walls of the epitaxial layers protect the individual dice from debris created by laser separation.

Abstract: The present invention provides semiconductor structures comprising a substrate and at least three III-V and/or II-VI multi junction building blocks, each comprising a p-n junction having at least two alloy layers, formed over the substrate, provided at least one multi-junction building block comprises II-VI alloy layers. Further described are methods for preparing semiconductor structures utilizing a sacrificial or etch-stop ternary III-V alloy layer over an III-V substrate.