In recent years the interest in Si/SiGe superlattice structures for a variety of semiconductor applications has grown. These layers are typically on the order of several nanometers with the desire to have extremely sharp or smooth interfaces. Characterization of such intricate layers for layer thickness, %composition and interface abruptness is extremely challenging. At EAG Laboratories, we have developed several metrologies to address this complex characterization problem. In this article we will discuss two commonly used techniques; Secondary Ion Mass Spectrometry (SIMS) and Scanning Transmission Electron Microscopy (STEM). Each technique has its own unique capabilities, but when used together they provide comprehensive characterization solution, especially for thin layers.