Characterization of USJ by XAS in GI geometry

Knowledge about the physics of Silicon based nanodevices is increasingly important for the development of future semiconductor technologies. The demand for device dimensions in the nm region leads to new challenges for production and characterization of components which are necessary for next generation electronic devices like micro processing units (MPU) or application specific integrated circuits (ASICS, e.g. CPU). Different implantation techniques capable to produce ultra shallow implantation profiles which are the basic module of these devices are under investigation. To understand the mechanisms of activation and deactivation of the dopant atoms dependent on various implantation techniques and subsequent thermal treatment the local atomic structure has to be probed. Therefore analytical techniques are required which are surface sensitive (in the nm region) and provide the needed structural information. Total reflection X-Ray Fluorescence (TXRF) analysis - or Grazing Incidence XRF (GI-XRF), which also includes angles larger than the angle of total reflection - is a well established tool for elemental analysis in the first few nanometers of a substrate able of giving information on the depth distribution of the elements. If synchrotron radiation is used as excitation source the performance of this technique is drastically increased and can be coupled to X-Ray absorption fine structure (XAFS) analysis. The investigation of the fine structure of the absorption coefficient allows determining parameters related to the local atomic structure of the sample. The combination of TXRF and XAFS analysis therefore allows the characterization of the dopant in ultra shallow implants distinguishing contributions from the topmost and deeper regions. Samples produced with different implantation techniques will be investigated utilizing XAFS analysis in TXRF geometry at the Stanford Synchrotron Radiation Laboratories (SSRL). A preliminary feasibility study already showed the high capability of method and facility. Method and data evaluation will be optimized and expanded to different experimental setups and analysis of the near edge region of the XAFS using theoretical data modeling.