Abstract: A vertical cavity surface emitting laser (VCSEL) including a first ohmic contact to the substrate formed on an upper surface of the device, instead of the conventional substrate bottom-side contact. The VCSEL is formed to include a hole made through the first distributed Bragg reflector (DBR) and into the material of the substrate itself. A metal layer is deposited at the bottom of the hole to contact the substrate, where the deposited metal layer creates a high quality ohmic contact by not also contacting the inner sidewalls of the hole (i.e., no “stringers” are formed within the hole).

Abstract: A method for forming a metal contact in a deep hole in a workpiece. A first hole is formed that extends from the upper surface of the workpiece to a substrate at the bottom of the hole. The hole is then filled with photoresist. Next, a photolithographic process is performed to create a second hole within the photoresist and to expose the substrate; and a wet etch is performed to remove a portion of the substrate. A layer of contact metal is then deposited on the surface of the photoresist. In the second hole, the metal layer is formed on the exposed surface of the substrate and on discontinuous portions of the photoresist on the sidewalls. A liftoff process is then used to remove the photoresist and the metal deposited on the photoresist while leaving the metal at the bottom of the second hole in contact with the substrate.