Application of Room-Temperature Photoluminescence for Characterizing Thermally Processed Cz Silicon Wafers
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Application Of Room-Temperature Photoluminescence For Characterizing Thermally Processed Cz Silicon Wafers F. Kirscht, B. Orschel, S. Kim, S. Rouvimov, B. Snegirev, M. Fletcher, M. Shabani1 and A. Buczkowski SUMCO USA 1351 Tandem Avenue, N.E. Salem, OR 97303, USA 1 SUMCO Japan 314 Nishisangao Noda-shi, Chiba-Ken, 278-0015 Japan ABSTRACT PL studies of oxygen precipitation related defects, stress relaxation related defects and doping striations in various silicon materials are presented. The sample spectrum includes a variety of dopant species, and the dopant concentration range covers several 1014 cm-3 to several 1019 cm-3. Lightly doped, precipitation-annealed polished wafers were intentionally contaminated with Fe, Ni and Cu. Several types of epi wafers based on heavily doped substrates have been investigated after full device processing. PL intensity in the investigated doping concentration range is controlled by three basic recombination mechanisms: radiative recombination competing with multi phonon Shockley-Read-Hall (SRH) and Auger recombination. SRH recombination is the major competing mechanism at low dopant concentration, and Auger recombination becomes important at increasing doping levels. Even though not yet fully understood, the PL technique applied in this study has generated practically useful results. INTRODUCTION Photoluminescence (PL) has been applied for characterizing a wide variety of silicon properties including the determination of boron, phosphorus [1] and carbon after irradiation [2], the analysis of metal-decorated stacking faults [3] and misfit dislocations [4], and gettering characteristics of CZ wafers [5]. In this paper we report further extension of PL applications, with focus on thermally processed CZ-Si wafers. Presented results are based on using a roomtemperature photoluminescence mapping (PLM) technique originally developed by BioRad. EXPERIMENTAL DETAILS The sample spectrum includes a variety of dopant species, and the dopant concentration range covers several 1014 cm-3 to several 1019 cm-3. The lightly boron-doped wafer set used got a 2-step precipitation annealing in nitrogen: 4h at 800°C, followed by 16h at 1000°C. Then, surface metals (Fe, Ni, Cu) at a concentration of (1.5-1.6) E13 cm-2 were introduced on one CZSi wafer side, and the metal in-diffusion step in nitrogen was 2h at 1000°C for Fe and 2h at 900°C for Ni and Cu. Three levels of oxygen precipitation related defects (OPDs) were generated using wafers with an oxygen concentration of (1.1, 1.4, 1.6) E18 cm-3. The second set of wafers consisted of various N/N+ epi wafers whereby N+ means substrate wafers heavily doped with either arsenic or antimony. Epi layers were lightly doped with phosphorus in this case. PL measurements were done using 532 nm and 827 nm excitation lasers, and applying F6.5.1 Downloaded from https://www.cambridge.org/core. La Trobe University, on 20 Jun 2020 at 13:18:24, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-719-F
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