  Group IV semiconductor alloys and heterostructures such as SiGe, GeSn, Ge/Si
and SiGe:C have been widely used and under extensive research for applications
in major microelectronic and photonic devices. In the growth and processing of
these materials, nanometer scale interdiffusion happens that are generally
undesirable for device performance. With higher Ge molar fractions and higher
compressive strains, Si-Ge interdiffusion can be much faster than dopant
diffusion. However, Si-Ge interdiffusion behaviors have not been well
understood until recent years. Much less studies are available for GeSn. This
review starts with basic properties and the applications of major group IV
semiconductors, and then reviews the progress made so far on Si-Ge and Ge-Sn
interdiffusion behaviors. Theories, experimental methods, design and practical
considerations are discussed together with the key findings in this field.
