US Patent 8120049 Light-emitting semiconductor device

A light-generating semiconductor region is grown on a substrate of electroconductive silicon or like light-absorptive material. An anode is placed atop the light-generating semiconductor region, and a cathode under the substrate. The light-generating semiconductor region and the substrate are encapsulated in an epoxy envelope. In order to prevent the substrate from absorbing the light that has been radiated from the light-generating semiconductor region and reflected back from the envelope, the substrate has its side surfaces covered by a reflector layer. The reflector layer has its surfaces roughened, as a result of the roughening of the underlying substrate surfaces by dicing, for scattering the incident light.