Deposition and patterning of Si/SiGe multiple stacks have been investigated by in situ monitoring techniques. Reflection supported interferometry has been applied to evaluate the thickness and optical parameters of each of the films during the deposition of the stacks by rapid thermal chemical vapor deposition. During patterning by reactive ion etching of these stacks, the nonselectivity of the etch process has been eluded by monitoring of the 265.1 nm Ge line using optical emission spectroscopy. In this way an etch stop can be achieved within any of the thin films of the stack. The results demonstrate an opportunity for in situ control, including end point detection of deposition and patterning of Si/SiGe multiple stacks.