Copper-silicide precipitates in silicon obtained after copper diffusion and quench in different liquids were studied by transmission electron microscopy and capacitance spectroscopy techniques. A correlation between the quenching rate, geometric size, and deep level spectra of the copper-silicide precipitates was established. The unusually wide deep level spectra are shown to be due to a defect-related band in the bandgap. The parameters of the band are evaluated using numerical simulations. A positive charge of copper-silicide precipitates in p-type and moderately doped n-type Si is predicted by simulations and confirmed by minority carrier transient spectroscopy measurements. Strong recombination activity of the precipitates due to attraction of minority carriers by the electric field around the precipitates and their recombination via the defect band is predicted and confirmed by the experiments. The pairing of copper with boron is shown to be an important factor determining the precipitation kinetics of the interstitial copper at room temperature.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.239.1.231 Downloaded on 2014-11-18 to IP
The density of states of two different dislocation types in silicon has been studied by computer modelling and fitting to available deep-level transient spectroscopic data. Our preliminary fit results indicate that one type, which is a dislocation bounding thin platelets consisting of two NiSi 2 (111) planes and supposed to be free of jogs, kinks, reconstruction defects and also point defect decoration, is associated with a one-dimensional band of states in the middle of the bandgap, 0.3 eV wide and with an electron occupation of 0.3 in the neutral state. Two fit parameters are not consistent with independent results and require the potential drop along the platelet to be incorporated in our model. For dislocations that move from a scratch under an applied stress at high temperatures, our fits, possible at present to only some of the data, show the existence of point defect clouds in the dislocation strain field and indicate the existence of core defects.
We report results of a detailed study of structural and electrical properties of copper silicide precipitates in silicon. Using conventional and high‐resolution transmission electron microscopy we observe that metastable platelets surrounded by extrinsic stacking faults form upon quenching from high temperatures. By ripening experiments at low temperatures as well as by a variation of cooling rates it is shown how homogeneous copper precipitation merges into the heterogeneous precipitation mode of colony growth. The application of recently developed criteria for the interpretation of deep level transient spectra from extended defects allows to conclude that deep electronic states associated with the precipitates have bandlike character.
We prove that for localized states at extended defects the high-temperature sides of deep-level transient spectra can be vrritten as a product of an amplitude function depending on the pulse length and a shape function depending on temperature.
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