The present invention concerns isolated nucleic acid molecules encoding the novel TIE ligands NL2, NL3 and FLS139, the proteins encoded by such nucleic acid molecules, as well as methods and means for making and using such nucleic acid and protein molecules. More specifically, the present invention provides a semiconductor layer that includes at least two impurities. The ROM lands intervene between consecutive ROM pits, whether or not a ROM groove is provided. The conductive interconnect includes ground conductors and digital signal conductors.