We demonstrate that the third elemental group-IV semiconductor, germanium, exhibits superconductivity at ambient pressure. Using advanced doping and annealing techniques of state-of-the-art semiconductor processing, we have fabricated a highly Ga-doped Ge (GeratioGa) layer in near-intrinsic Ge. Depending on the detailed annealing conditions, we demonstrate that superconductivity can be generated and tailored in the doped semiconducting Ge host at temperatures as high as 0.5 K. Critical-field measurements reveal the quasi-two-dimensional character of superconductivity in the approximately 60 nm thick GeratioGa layer. The Cooper-pair density in GeratioGa appears to be exceptionally low.

Amorphization of 6H-SiC with 200 keV Ge+ ions at room temperature and subsequent ion-beam-induced epitaxial crystallization (IBIEC) with 300 keV Si+ ions at 480 °C have been studied by Rutherford backscattering spectrometry/channeling and transmission electron microscopy analysis. Experimental results on amorphous layer thicknesses have been compared with trim calculations in association with the critical energy density model. Density changes during amorphization have been observed by step height measurements. Particular attention has been directed to the crystal quality and a possible polytype transformation during the IBIEC regrowth. The IBIEC process consists of two stages and results in a multilayer structure. In the initial phase an epitaxial growth of 6H-SiC has been obtained. With increasing IBIEC dose the epitaxial growth changes to columnar growth and is stopped by polycrystallization of 3C polytype in the near-surface region.

The density of amorphous SiC layers formed by 2 MeV Si+ implantation into single-crystalline 6H–SiC was measured by x-ray reflectometry and compared with the results of step height measurements. Reactive ion etching was used to investigate the density as a function of depth. The density of the as-amorphized SiC is about 12% less than that of the crystalline material. Within experimental accuracy, the density reduction is homogeneous across the whole layer thickness. Low-temperature annealing leads to the formation of relaxed amorphous SiC with a density about 7% below the crystalline one. These large density changes are in contrast to results in amorphous Si. They can be explained by the high atomic density of SiC and the chemical disorder in the amorphous state of SiC.

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Shallow n+ layers in Ge are formed by phosphorus implantation and subsequent millisecond flash lamp annealing. Present investigations are focused on the dependence of P redistribution, diffusion and electrical activation on heat input into the sample and flash duration. In contrast to conventional annealing procedures an activation up to 6.5× 1019 cm-3 is achieved without any dopant redistribution and noticeable diffusion. Present results suggest that independently of pretreatment the maximum activation should be obtained at a flash energy that corresponds to the onset of P diffusion. The deactivation of P is explained qualitatively by mass action analysis which takes into account the formation of phosphorus-vacancy clusters