Abstract: A semiconductor device comprising, a plurality of semiconductor layers having an outer semiconductor layer, and a contact layer uniformly and entirely covering said outer semiconductive layer and having over its entire surface the same material composition and abutting over its entire surface directly against said outer semiconductive layer but having only on a partial region of its surface a conductive transition to said outer semiconductive layer. The conductive transition being obtained by alloying said partial region by means of a focused laser beam pulse heating only said partial region of the contact layer to the alloying temperature, whereby alloy constituents of the melted contact material wetting said outer semiconductive layer diffuse only in a superficial zone of said outer semiconductive layer.