Dr. Junji Yamanaka
Dr. Junji Yamanaka
University of Yamanashi, Japan
Title: A challenge to analyze slight change of lattice spacing in a compositionally step-graded SiGe thin film using STEM moiré
In the field of semiconductor devices, it is very important to study lattice strains or lattice–space distributions because they are strongly affected electric properties. Recently very unique new method to analyze lattice strains using STEM moiré has been proposed by Y. Kondo and N. Endon, and by other researchers. In this technique,the moiré between the crystal lattices and the scanning lines controlled by STEM is utilized to show lattice-spacing distribution. Our groupalso reported our experimental results about STEM moiré observation of Ge/Si. In this study, this new technique is applied to the compositionally step-graded SiGe thin film which is grown onto Si (110) substrate by MBE. The composition step between the each SiGe layers is about 2at%. (From pure Si to Si-22at%Ge.) Image analysis software “sMoiré” produced by HREM Research Inc. is utilized in this study. The results show the potential of this technique that can distinguish a slight difference of the lattice spacing between the SiGe layers.
Junji Yamanaka. He received his master-of-engineering degree from Nagoya Institute of technology in Japan, and his doctor-of-engineering degree from Tokyo Institute of technology in Japan. He started his professional career in a private company, Nissan ARC Ltd. Then he worked for McMaster University in Canada as a post-doctoral fellow and for the University of Yamanashi in Japan as a research associate. His current position in the University of Yamanashi is an associate professor of the Center for Instrumental Analysis. His selected research achievements are about microstructure of semiconductors, intermetallic compound, and other inorganic materials, such as “STEM Moiré Observation of Lattice-Relaxed Germanium Grown on Silicon”, “Microstructure Change of B2 Precipitates in an Fe-Al-Ni Alloy Due to Two-Step Heat-Treatment”, “Cross-Sectional Observation of Surface Graphitization in Furan-Resin-Derived Carbon”.