Atomic-scale strain analysis for advanced Si/SiGe heterostructure by using transmission electron microscopy

Three-dimensional stacked transistors based on Si/SiGe heterojunction are a potential candidate for future low-power and high-performance computing in integrated circuits. Observing and accurately measuring strain in Si/SiGe heterojunctions is critical to increasing carrier mobility and improving device performance. Transmission electron microscopy (TEM) with high spatial resolution and analytical capabilities provides technical support for atomic-scale strain measurement and promotes significant progress in strain mapping technology. This paper reviews atomic-scale strain analysis for advanced Si/SiGe heterostructure based on TEM techniques. Convergent-beam electron diffraction, nano-beam electron diffraction, dark-field electron holography, and high-resolution TEM with geometrical phase analysis, are comprehensively discussed in terms of spatial resolution, strain precision, field of view, reference position, and data processing. Also, the advantages and critical issues of these strain analysis methods based on the TEM technique are summarized, and the future direction of TEM techniques in the related areas is prospected.