Scanning moiré fringe imaging for quantitative strain mapping in semiconductor devices

The development of a method for the precise measurement of strain fields in semiconductor devices has become a critical requirement because the electrical performances of the devices are greatly influenced by the strain induced in their structures. We applied scanning moiré fringe imaging to demonstrate the quantitative strain mapping of a Si/Si_1−xGe_x interfacial layer. The strain field was measured at a nano-meter scale spatial resolution, with a detection precision of 0.1%. The maximum value of the strain was measured to be 1.1% ± 0.1%, which is consistent with the direct measurement by high-resolution scanning transmission electron microscopy image.