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The oxygen precipitation behavior in large diameter (300 mm) Czochralski silicon polished wafers with initial oxygen concentrations between 25-36 parts per million atomic and low carbon content, has been studied following two step heat-treatments (lowhigh annealing). It was found that an oxygen precipitation retardation and recovery phenomena occurred. Transmission electron microscopy observations showed that extended defect formation is drastically changed from punched-out dislocations in precipitate retardation samples, to stacking faults in precipitation recovery samples. The precipitation retardation phenomenon is consistent with a previous model on smaller diameter wafers; however, the current experimental results for 300 mm wafers indicate platelet precipitate growth during the first low temperature annealing plays a key role in the oxygen precipitation recovery phenomenon.

Post-deposition rapid vacuum annealing of tantalum nitride (Ta2N) thin film resistors (TFR) was successful in improving the temperature coefficient of resistance (TCR) to ±5 ppm/°C with starting TCR at about −140 ppm/°C. A subsequent aging study revealed degradation of the nichrome (NiCr) contact interlayer. Two improved contact layers, TiW and Tamelox (Ta/NiCr), were compared. The structural grain growth induced by the annealing effect resulted in Ta2N films having 100–1000 Å polycrystals in an amorphous matrix. The corresponding current conduction mechanisms were identified with a substrate-assisted tunneling model. The frequency response predicted potential applications to 100 GHz.

Encouraging characterization data for 300 mm polished developmental wafers has been obtained, indicating individual parameter data in some cases comparable to or even exceeding state-of-the-art 200 mm epitaxial wafers. Initial oxygen precipitation data in 300 mm sectioned wafers indicates behavior consistent with previously observed phenomenon. Nevertheless, extensive work is required for further clarification and detailed comparison to 200 mm behavior.

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