Abstract: A 10.sup.-6 ohm cm.sup.2 ohmic contact is provided by formation of a 20-50 Angstroms deep surface region with a net donor density of higher than 5.times.10.sup.19 /cc. An amphoteric dopant of Si or Ge is incorporated in a pinned Fermi level condition so that an enhanced surface donor concentration occurs.

Abstract: A semiconductor processor for signals such as are conveyed by fiber optics wherein the processor structure accommodates lattice mismatch and minimizes the effect of misfit dislocations. The structure permits using materials having favorable absorption properties at the 1 micrometer wavelength of optical signals. A binary semiconductor is employed with graded regions produced by adding a different third ingredient in two places so that a wide band optically transparent emitter with a graded base and graded collector are provided. The ingredients impart a strong absorption in the optical signal wavelength together with superior semiconductor carrier transit time. A structure for a silicon and germanium oxide based optical signal fiber uses a GaAlAs emitter, a base that is graded to Ga.sub.0.25 In.sub.0.75 As at the collector and then back to GaAs at the substrate.