AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP28
Local Structure Around Germanium Atoms in SiGe Thin Films

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: Y. Uehara, Mitsubishi Electric Co., Japan
Authors: Y. Uehara, Mitsubishi Electric Co., Japan
K. Kawase, Mitsubishi Electric Co., Japan
J. Tsuchimoto, Renesas Co., Japan
Correspondent: Click to Email
SiGe thin films are widely studied in order to apply them as the channel layer for LSI of the next generation, because they show superior electronic properties than the current silicon channel. More germaniums in film enhance the electron mobility, while the lattice mismatch of the film with the substrate becomes large, so it is important to control the concentration of germanium in the film. Also, it should be important to control how the germanium atoms are involved in the film, however, there are few information on them. In this study, we have applied XAFS technique to investigate the local structure around germanium atoms in SiGe thin films. SiGe films were prepared by CVD method on Si(100) wafers. Si/Ge ratio of the films was controlled by the flow rate of the origin gases. The germanium concentration and the thickness of the films were confirmed by X-ray locking curve method and X-ray reflectivity method, respectively. XAFS measurements at Ge-K absorption edge were performed at BL16B2 of SPring-8. The Si(311) double crystal monochromator and the Rh-coated cylindrical mirror were used, and electrons emitted from the sample surface were collected using a conversion electron yield detection system. We could not find any changes in the Ge-K XANES region among the samples with different germanium concentration. The standard EXAFS analysis was performed to elucidate the local structure around the germanium atoms in the films. The curve fitting analysis revealed that the germanium atoms in as-deposited SiGe thin films make complete solid solution with silicon, do not conform micro-clusters of germanium, at least when the germanium concentration is less than 20%.