The fabrication of Si- and compound semiconductor-based devices involves a number of steps ranging from material growth to pattern definition by lithography, and ultimately, pattern transfer by etching/deposition. The key to device manufacturing, however, is reproducibility, low cost and high yield. Diagnostic techniques allow correlation between processing and actual device performance to be established. Researchers from universities, industry and government come together in this book to examine the advances in diagnostic techniques that provide critical information on structural, optical and electrical properties of semiconductor devices, as well as monitoring techniques for equipment/processes for control and feedback. The overriding goal is for rapid, accurate materials characterization, both in situ and ex situ. Topics include: in situ diagnostics; proximal probe microscopies; optical probes of devices and device properties; spectroscopic ellipsometry/structural diagnostics; and material analysis - X-ray techniques, strain measurements and passivation.