Discrete control of individual dopant or impurity atoms is critical to the electrical characteristics and fabrication of silicon nanodevices. The unavoidable introduction of defects into silicon during the implantation process may prevent the uniform distribution of dopant atoms. Cottrell atmospheres are one such nonuniformity and occur when interstitial atoms interact with dislocations, pinning the dislocation and trapping the interstitial. Atom probe tomography has been used to quantify the location and elemental identity of the atoms proximate to defects in silicon. We found that Cottrell atmospheres of arsenic atoms form around defects after ion implantation and annealing. Furthermore, these atmospheres persist in surrounding dislocation loops even after considerable thermal treatment. If not properly accommodated, these atmospheres create dopant fluctuations that ultimately limit the scalability of silicon devices.

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An analysis of interfacial energies in a solid-liquid system showed that complete penetration of a liquid along grain boundaries in a microstructure forming during liquid-phase sintering is not necessarily associated with complete wetting or spreading at the solid-liquid interface. Investigations were made on the penetration of Ca0-A1,03-Si02 glasses into dense polycrystalline aluminas. Initial penetration was along threegrain junctions or grain boundaries by a solution/reaction between the liquid and defect-containing alumina along interfaces. Degree of penetration was variable, and it was dependent on internal strain and MgO addition. Extended heat treatments reduced liquid penetration.

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