There is a wide set of literature reports that suggest that over-coordinated oxygen or self-interstitials are, directly or indirectly, the chemical bridge between thermal donors, oxygen precipitates and dislocations, capable of supporting a common origin of their emission features in the 0.7-0.9 eV range. Finding the experimental proof of these suggestions was the aim of this present work, which required both appropriate preparation of samples and their careful optical, electrical and microscopical characterization. We were able to show not only that the photoluminescence emissions from oxide precipitates could be correlated to their density and to the presence of closed dislocation rings around them, but also that the precursors of dislocations are optically active as well. For samples thermally annealed in the range of thermal donors, we were able to show that their optical activity seems to be correlated to a transition from a shallow donor level of thermal donors to a deep level of a CiO2 complex.

A suitable choice of one sample among several silicon wafers subjected to two-step thermal treatments for oxygen precipitation permits to reveal a complete series of infrared absorption peaks related to the precipitates formed in the crystal. Structured spectra are observed at 7 K and can be interpreted as due to SiO2 precipitates with different shapes and concentrations.

Silicon crystals grown with the Czochralski method are still the most common material used for the production of electronic devices. In recent years, a growing need of large diameter crystals with increasingly higher doping levels is observed, especially to support the expanding market of discrete devices and its trend towards lower and lower resistivity levels for the silicon substrate. The growth of such heavily doped, largediameter crystals poses several new challenges to the crystal grower, and the presence of a high dopant concentration in the crystal affects significantly its main properties, requiring also the development of dedicated characterization techniques. This paper illustrates the recent advances in the growth and characterization of silicon crystals heavily doped with antimony, arsenic, phosphorus and boron.

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The applications of minority carrier recombination lifetime measurement techniques to a variety of problems associated with the manufacture and use of modern CZ silicon are discussed. The uses of the ELYMAT and microwave photoconductive decay techniques applied to issues of transition metal contamination, ultra long carrier lifetimes, oxygen clustering and precipitation, intrinsic point defect reactions and gettering phenomena are considered. The uses and limitations of injection level control and surface recombination velocity measurement are also discussed.

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