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Characteristics and Evaluation Methods of Carrier Recombination Lifetimes in High-quality Silicon Wafers Pages: 15 Published: Jan 1998
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View License Agreement Lifetime quality and the evaluation methods are discussed for (i) high-quality bulk Czochralski-grown crystals, (ii) polished wafers, and (iii) epitaxial layers in p/p+ wafers, (i) To determine the bulk lifetime value accurately for high-quality Si, it is important to measure a bulk sample 1–2cm-thick by a photoconductive decay method based on JIS: H0604-1995 or ASTM: F28-75. This high-sensitivity measurement reveals a new phenomenon of oxygen-related recombination-enhanced lifetime shift. (ii) For wafer analyses using an iodine-ethanol chemical passivation technique, the surface recombination velocities are determined precisely, (iii) To evaluate epi-layer lifetime qualities of p/p+ wafers, “Short-Wavelength Laser-Excited Photoluminescence (PL) Technique” is useful. Applying this technique to a heavy-metal gettering study, it is found that, even in p/p+ wafers with excellent Fe gettering capability, optimization of the substrate oxygen precipitation and the stability of the gettering sites are important. | ||
