Precipitation of Copper and Cobalt at Grain Boundaries in Silicon

Abstract

The precipitation of copper and (radioactive) cobalt at low energy grain boundaries in polycrystalline silicon and bicrystals is investigated. The metals are diffused in from a surface source between 800 - 1000 °C and the precipitation after cooling down is studied by TEM (for Cu) and Mößbauer spectroscopy (for Co). The precipitates are metal suicides. For copper it is shown that they appear in form of colonies containing hundreds of precipitates with a particle size between 5-60 nm. In the grain boundary they nucleate preferentially at dislocations and steps. The distribution and size of the precipitates depend on the cooling rate after the diffusion. In the vicinity of the grain boundary the volume is depleted from the impurities.

Internal friction due to kink motion and kink pair formation in intrinsic and n-doped germanium

“…The temperature of maximum 1 is reached by MOller only, but the resolution of his measurements (5 x Ohori and Sumino interpreted their peaks a t 64 and 97 K [14] as due to the motion of single kinks on screws and 60" dislocations, resulting in an activation eiithalpy of -0.1 eV and a frequency factor of f, = 1011 Hz. To explain the small relaxation strength of their peaks, the authors have to assume an average distance L of about 5 n m for the unsurmountable obstacles for the kinks on the dislocation (see (6)). Considering the high purity of Ge single crystals these obstacles could only be intrinsic defects on the dislocations.…”

“…So it must be emphasized that H , and H B can be interpreted only as the activation enthalpies for KM and K P F on single partial dislocations [6], while the existence of extrinsic obstacles and correlation effects of the partial dislocations [37] can be ruled out.…”