Applications of UV-Raman Spectroscopy to Microelectronic Materials and Devices

Raman spectroscopy is a powerful technique for characterization of microelectronic materials and device structures. However, the commonly used visible Raman spectroscopy technique is severely limited in both lateral and depth resolution in applications to rapidly shrinking ULSI device structures. The UV micro-Raman technique can greatly enhance the spatial resolution by taking advantage of the shorter wavelength and much smaller optical penetration depth ( < 10 nm in Si at 325 nm versus 400 nm in the visible). We present UV micro-Raman mapping of stress and crystallinity in shallow trench isolated (STI) CMOS devices. The shorter optical penetration depth in Si and other wide-gap materials also makes UV-Raman spectroscopy very appealing in characterizing thin films of such materials. Examples will be given in characterization of ultrathin strained Si channels on SiGe buffer and thin SrTiO3 and SiN dielectric films on Si.