An opto-electronic semiconductor element has a radiation emitting or receiving, that is, radiation active semiconductor chip secured to an electrically conductive base frame. One, or a plurality of chips, are surrounded by a housing which may be integral with or have, separately, a cover. All materials of the housing, as well as of the conductive base frame, have mutually matching thermal coefficients of expansion within the temperature ranges which arise during manufacture and in application of the semiconductive element, singly or as a plurality in a common housing. Glass, quartz glass, ceramic or glass ceramic are suitable for the housing or parts thereof; the conductive base frame is preferably made of cladded or jacketed copper wire or strip with an iron-nickel core. Assembling a plurality of chips in a housing which has a luminescence conversion layer, e.g. a phosphor applied thereto, permits construction of a flat light source.