Measurement of in-plane and depth strain profiles in strained-Si substrates

• Published in: Solid-state electronics 2007-02, Vol.51 (2), p.219-225
• Main Authors: Ogura, Atsushi, Kosemura, Daisuke, Yamasaki, Kosuke, Tanaka, Satoshi, Kakemura, Yasuto, Kitano, Akiko, Hirosawa, Ichiro
• Format: Article
• Language: English
• Subjects: Applied sciences; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Integrated circuits; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2007.01.002

Both in-plane and depth strain profiles in commercial strained-Si substrates were evaluated by UV-Raman mapping and in-plane X-ray diffraction (XRD) techniques. A 200 mm wafer mapping showed the strain at the edge region was larger than that in the center for the Bulk substrate, while the strain varied gradually from one side to the other side in the silicon–germanium-on insulator (SGOI) and strained-silicon-on-insulator (SSOI) substrates. Cross-hatch contrasts corresponding to misfit dislocations were observed in the magnified close-up for each substrate. The Bulk and SGOI substrates had cross-hatch-like morphology corresponding to the strain variation, while no specific feature was observed on the SSOI surface. Using in-plane XRD measurement, a variation in strain depth was detected for the Bulk substrate, although the strain was quite uniform along the depth direction for the SGOI and SSOI substrates. The in-plane XRD peak widths of strained-Si substrates were much larger than that of Cz–Si, reflecting poor crystal quality.