Diffusion of silicon (Si) and germanium (Ge) in silicon-germanium Si1−xGex-isotope heterostructures with Ge contents x=0, 0.05, 0.25, 0.45, and 0.70 was investigated in a temperature range between 690 and 1270 °C. The concentration profiles of the stable Si-isotopes and Ge-isotopes were recorded by means of time-of-flight secondary ion mass spectrometry. Analysis of the experimental profiles shows that the Si and Ge diffusion coefficients in elemental Si agree within experimental accuracy. However with increasing Ge content the diffusion of Ge gets increasingly faster compared to that of Si. An Arrhenius type temperature dependence of diffusion is observed for all compositions with slightly lower values for the activation enthalpy of Ge compared to Si. The more pronounced Ge diffusion indicates that with increasing Ge concentration the diffusional jumps of Ge atoms become more successful compared to those of Si. This trend is explained with an increasing contribution of vacancies to self-diffusion in Si1−xGex with x. In contrast to earlier results the composition dependence of the activation enthalpy of self-diffusion reveals an upward bowing. A similar composition dependence is reported for the arsenic (As) and antimony (Sb) diffusion in SiGe and is predicted theoretically for the stability of phosphorus-vacancy and arsenic-vacancy pairs in SiGe. The nonlinear behavior seems to be a general trend and accordingly mainly a consequence of the SiGe alloy system.

We use micro-bubble based thermo-optical tweezers to simultaneously synthesize, dope, and pattern conducting polymers to obtain unprecedented conductivity values.

The formation and evolution of small cluster defects in 500 eV, 1×1015 cm−2 boron-implanted silicon is investigated. These clusters are identified by high-resolution transmission electron microscopy (TEM) as small dislocation loops lying on {100} planes with an interstitial character. Weak-beam dark-field TEM analysis shows that, during annealing at 650 °C, they evolve following an Ostwald ripening mechanism. Spike anneals at high temperatures make them dissolve but an immobile boron peak is still detected in the secondary ion mass spectroscopy profiles. Upon oxidation, the average size of the clusters increases, while boron electrical deactivation occurs. These results strongly indicate that the observed clusters contain both boron interstitials and silicon self-interstitials atoms.

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Fluorine-enhanced boron diffusion in germanium-preamorphized silicon J. Appl. Phys. 98, 073521 (2005); 10.1063/1.2084336 Activation improvement of ion implanted boron in silicon through fluorine co-implantation J.