Gold on graphene as a substrate for surface enhanced Raman scattering study

In this paper, we report our study on gold (Au) films with different thicknesses deposited on single layer graphene (SLG) as surface enhanced Raman scattering (SERS) substrates for the characterization of rhodamine (R6G) molecules. We find that an Au film with a thickness of ~7 nm deposited on SLG is an ideal substrate for SERS, giving the strongest Raman signals for the molecules and the weakest photoluminescence (PL) background. While Au films effectively enhance both the Raman and PL signals of molecules, SLG effectively quenches the PL signals from the Au film and molecules. The former is due to the electromagnetic mechanism involved while the latter is due to the strong resonance energy transfer from Au to SLG. Hence, the combination of Au films and SLG can be widely used in the characterization of low concentration molecules with relatively weak Raman signals.Comment: 11 pages, 4 figure

UV Raman studies of channel stress in transistors with embedded SiGe source and drain

Channel strain engineering is important for improving the performance of metal-oxide-semiconductor (MOS) devices today. UV Raman spectroscopy is commonly used for stress measurements in microelectronics applications, but its use in channel stress studies of advanced transistors in sub-100nm nodes is relatively unexplored. This thesis presents a low-cost method for rapid characterization of channel stress of 45nm-node transistors with embedded SiGe source and drain, using UV Raman spectroscopy. Results of using a micro-meter sized laser beam to study the channel stress of repeating transistors are presented and discussed. The effects of changing the gate pitch as well as the impact of implantation and annealing on the channel stress are investigated. Simulation results are also included to provide insight into the interaction of light with the structures studied. The measurement approach presented in this thesis can be an attractive alternative to other approaches that require more time and resources to carry out.DOCTOR OF PHILOSOPHY (SPMS

High-mobility germanium-tin (GeSn) P-channel MOSFETs featuring metallic source/drain and sub-370°C process modules

10.1109/IEDM.2011.6131569Technical Digest - International Electron Devices Meeting, IEDM16.7.1-16.7.3TDIM