Strain evaluation of strained-Si layers on SiGe by the nano-beam electron diffraction (NBD) method

The strain relaxation within a strained-Si layer may be one of the key issues in the development of strained-Si MOSFET devices for high-performance ULSIs. In order to investigate the strain relaxation within the thin strained-Si layers, a new characterization technique for directly evaluating the strain variation within the layers is required. Hence, we have developed the nano-beam electron diffraction (NBD) method which has a lateral resolution of less than 10 nm and a strain resolution of 0.1%. In this paper, we discuss detailed investigations to determine whether the NBD method can be utilized to clarify the strain within a strained-Si layer grown on an SiGe structure and a MOSFET device.