Silicidation in Ni-Si System
Silicide formation induced by thermal annealing in Ni/Si thin film system has been investigated using glancing incidence X-ray diffraction. Silicide formation takes place at 600degC with Ni2Si, NiSi and NiSi2 phases co-existing with Ni. Complete conversion of intermediate silicide phases to the final NiSi2 phase takes place at 900degC. A comparison of the experimental results in terms of annealing temperature, Ni thickness, and dopant impurities with Ni-Si phases is presented. Nickel silicide (NiSi) is emerging to be the choice material for contact application in semiconductor device processing for sub_65 nm technology node and beyond. The focus of present work is to facilitate better understanding of the influence of thermal budget on nickel silicide solid-state reaction. Requirements for low temperature anneal and improving within wafer sheet resistance uniformity pose challenges for conventional lamp-based rapid thermal processing (RTP) due to lamp response effects on temperature controllability. Evolution of the nickel-rich silicide phase as a function of temperature is recorded using X-ray diffraction (XRD) techniques. It is postulated that lowering the Ni2Si/Si interface energy favors the delay of the agglomeration of the NiSi.
XTEM Studies of Nickel Silicide Growth on Si(100) Using a Ni/Ti Bilayer System
Using a Ni/Ti bilayer system on Si(100) substrates we found a preferential growth of epitaxial NiSi2 at reaction temperatures of about 475 °C. This is attributed to the relatively slow Ni transport rate through the Ti layer, which acts as a diffusion rate limiting barrier. Annealing temperatures of 500 °C lead to the formation of mainly orthorhombic NiSi with a small fraction of NiSi2. The silicide phases grow with well defined orientations with respect to the underlying Si lattice for annealing temperatures up to 475 °C. 
 
 
 
An einem Ni/Ti-Zweischichtsystem auf Si(100)-Substraten fanden wir ein bevorzugtes Wachstum von epitaktischem NiSi2 bei Reaktionstemperaturen von 475 °C. Das wird auf die geringe Transportrate fur Ni durch die Ti-Schicht, die als Barriere zur Begrenzung der Diffusionsrate dient, zuruckgefuhrt. Temperaturen von 500 °C fuhren zur Bildung von hauptsachlich orthorhombischem NiSi und, in geringem Mas, von NiSi2. Bis zu Temperaturen von 475 °C wachsen die Silicidphasen mit definierten Orientierungen in Bezug auf das darunterliegende Si-Gitter.
Surface roughness monitoring by singular spectrum analysis of vibration signals
Abstract This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.