Non-destructive, wafer scale method to evaluate defect density in heterogeneous epitaxial layers

摘要

A semiconductor material stack of, from bottom to top, a first semiconductor material having a first lattice constant and a second semiconductor material having a second lattice constant that may or may not differ from the first lattice constant and is selected from an III-V compound semiconductor and germanium is provided. The second semiconductor material of the semiconductor material stack is then scanned using an atomic force microscope (AFM) operating in a tapping mode to provide an AFM image of the second semiconductor material of the semiconductor material stack. The resultant AFM image is then analyzed and crystal defects at a topmost surface of the second semiconductor material of the semiconductor material stack can be measured.