Leakage currents of n+-p-diodes, made on four different groups of p-type silicon substrates, are investigated at temperatures between 50 and 120'C. At these temperatures, diffusion of thermally generated minority carriers from the bulk is the dominant leakage current mechanism and determines the holding time of dynamic memories. Measurements at these temperatures show that for Czochralsky-grown wafers (CZ) with a high interstitial oxygen concentration as is used for intrinsic gettering, the leakage current densities are about 1OX higher than for CZ wafers with a low oxygen concentration or floating-zone wafers (FZ), and are about lOOx higher than for p-p +-epitaxial substrates. Simple analytical formulas explaining these large differences will be presented. Finally a short discussion about the optimum substrate for future high-density memories will be given.

The properties of a Pd—Au complex in n‐type Si are investigated by DLTFS (deep level transient Fourier spectroscopy) techniques. In n‐type Si the energy level of the Pd—Au complex is slightly shifted with isochronal annealing and does not display stable properties. The defect reaction of Pd—Au is explained by an “enhanced kick‐out” mechanism represented by the reaction equation Aui + Pds → Aus + Pdi, where interstitially diffusing gold replaces substitutional palladium. This reaction is similar to the Au—Rh defect reaction. The results of the investigations of the properties of the Pd—Au complex in p‐type Si will be published later.

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