Alex See

Micro‐Raman Spectroscopy Investigation of Nickel Silicides and Nickel (Platinum) Silicides

The formation of silicides has been successfully monitored by Raman spectroscopy. silicides formed at different annealing temperatures using rapid thermal annealing were analyzed using Rutherford backscattering spectroscopy and X‐ray diffraction. Raman spectroscopy was further used to examine these samples. The results showed that Raman spectroscopy could accurately identify the phases of silicides formed at various temperatures. These findings were used to demonstrate the increased thermal stability of by the addition of . This study demonstrates the applicability of Raman spectroscopy for monitoring the formation of . which was suggested to be the future silicide for deep submicrometer integrated circuit processing. Raman spectroscopy offers a unique tool for phase identification at localized areas and mapping characterization of silicides with micrometespatial resolution. ©2000 The Electrochemical Society

Applications of micro-Raman spectroscopy in salicide characterization for Si device fabrication

This article demonstrates that micro-Raman spectroscopy is a very powerful technique for the study of a variety of problems related to metal salicides for Si device fabrication. In addition to its versatile nature and ease of use, this technique provides some unique capabilities that complement the commonly used tools for Si device characterization. Phase identification of the TiSi2 C54, C49, and C40 phases as well as NiSi and NiSi2 can be achieved easily using Raman spectroscopy. The phase transition process from NiSi to NiSi2 has also been successfully monitored. Raman band assignments for C40 TiSi2 and NiSi are also made in order to have a better understanding of the Raman spectra. Thickness measurement of ultrathin salicide films from 45 nm down to 6 nm has been accurately performed using attenuation of the Si Raman signal at 520 cm−1, and film uniformity can also be evaluated using the same peak. Local orientations of the NiSi grains are studied by the relative intensity of the NiSi Raman peaks with ...

Excimer Laser-Induced Ti Silicidation to Eliminate the Fine-Line Effect for Integrated Circuit Device Fabrication

In this paper laser thermal processing (LTP) is applied to induce the Ti silicide formation in replacement of rapid thermal annealing (RTA) in narrow lines. Results show that the C40 TiSi 2 is synthesized after LTP in both large and small features. With this interfacial C40 TiSi 2 , the C54 TiSi 2 -phase formation temperature can be lowered by 100°C during subsequent annealing. The C40-C54-phase transition is also achievable with low temperature treatment. Most importantly, the C54 TiSi 2 growth is linewidth independent down to at least 0.25 μm using LTP followed by RTA. LTP provides a possible technique to extend the application of TiSi 2 to subquartermicrometer technologies.

Classification of Palladium Nucleation Processes Based on Nucleus Size Distribution

Catalytic Pd nucleation is a crucial preparatory step for the activation of electroless (EL) Cu deposition. We have observed that the time evolution of catalytic Pd nucleation can be classified into stages according to the Pd nuclei density and the nucleus size distribution. We have tentatively labeled these stages as growth, secondary nucleation, and ripening. The stage identification is assisted with the observation of distribution range and semi-interquartile range. In this study we found that the smoothest EL Cu film can be achieved with Pd activation corresponding to the beginning of the ripening stage.

Layer Inversion of Ni(Pt)Si on Mixed Phase Si Films

The formation of Ni silicides has been improved with Ni(Pt)-silicidation on the mixed phase Si films which were grown using the rapid thermal chemical vapor deposition technique. The Ni(Pt)Si was stabilized up to 800°C and layer inversion was retarded beyond 600°C. The enhanced stability of Ni(Pt)Si is attributed to the change in Gibbs free energy. The reduced layer inversion is due to the modification of the Si microstructure that has played an important role in the layer inversion. The enlarged poly-Si grains from the mixed phase films are due to the silicide enhanced mediated crystallization using NiSi 2 precipitates as seeds besides the preexisting Si crystallites.

Application of phase-imaging tapping-mode atomic-force microscopy to investigate the grain growth and surface morphology of TiSi2

Phase-imaging tapping-mode atomic-force microscopy (TM AFM) has been used to study the grain size of TiSi2 films. Presently, there are few reports in the literature on the application of the phase imaging technique for grain size characterization. In this study, very clear images of TiSi2 grains have been obtained and compared to transmission electron microscopy micrographs. For the first time, both triple point C54–TiSi2 nuclei and C49-phase grains have been clearly identified with this technique. C49 and C54–TiSi2 nuclei are about 50 and 15 nm, respectively at 650u200a°C. The C49-to-C54 phase transformation of TiSi2 is confirmed by x-ray diffraction. This study demonstrated that TM AFM can be used for grain size characterization with high accuracy and efficiency.

Effect of Fluorine Co-Implant on Boron Diffusion in Germanium Preamorphized Silicon During Post-LSA Rapid Thermal Annealing

Fluorine co-implant has been shown to reduce boron transient enhanced diffusion and deactivation when coupled with conventional spike rapid thermal anneals (RTA). For ultrashallow junction formation beyond the 45 nm technology node, non-melt laser spike anneal (LSA) is a promising diffusion-less annealing candidate. In this paper, the effect of fluorine co-implant on boron diffusion during LSA and the subsequent post-LSA thermal budget is evaluated. Silicon wafers were implanted with germanium, fluorine, and subsequently boron ions. Non-melt LSA was carried out at a temperature range from 1150 to 1350°C, followed by RTA at 825°C for 30 s. Secondary ion mass spectrometry confirms that in the presence of fluorine, retarded boron diffusion is observed at LSA temperatures below 1250°C. As the LSA temperature is increased or when a subsequent soak RTA is carried out, enhanced boron diffusion is observed. The reduced boron diffusivity at LSA temperatures below 1250°C is attributed to the efficient capture of interstitials released from the end-of-range defects by fluorine-vacancy clusters during the millisecond anneal. As the thermal budget is increased, excess interstitials caused by the fluorine implant are released, thus increasing the boron diffusion.

Channel stress measurements of 45 nm node transistors with embedded silicon-germanium source and drain using ultraviolet Raman spectroscopy

We report the use of ultraviolet Raman spectroscopy to measure the average channel stress for 45 nm node transistors with embedded silicon-germanium (SiGe) source and drain. Direct probing of the channel for stress measurements was made possible by removing the polycrystalline silicon gate using a simple and cost-free approach. We demonstrate the feasibility of this method for measuring channel stress of dense transistor structures with varying pitch lengths, with ∼80u2002nm SiGe selectively grown in the source and drain regions.

Enhancement Effect of C40 TiSi2 on the C54 Phase Formation

We report on the formation of a new material, C40 TiSi 2 , using pulsed laser annealing. On the basis of this laser-induced C40 TiSi 2 , the growth of the technologically important C54 phase is significantly promoted and can be accomplished with a subsequent rapid thermal anneal or furnace annealing at temperatures far below that for the normal C54 formation. The undesirable C49 TiSi 2 is completely bypassed. C40 TiSi 2 can also he easily transformed to the C54 phase with thermal treatments and result in the formation of a pure C54 TiSi 2 layer. The synthesis of C40 phase without the additional refractory metals and its promotion effect on the C54 phase formation have great potential for applications in the integrated circuit industry for 0.10 μm technology node and beyond.

Loading Effect of Selective Epitaxial Growth of Silicon Germanium in Submicrometer-Scale Silicon (001) Windows

We report different loading effects in selective epitaxial deposition of silicon germanium on silicon (001) using different silicon sources, such as silane or dichlorosilane, and other conventional sources, such as germane, and hydrogen chloride in hydrogen carrier gas, in a low-pressure chemical vapor deposition system. Silane leads to lower relative deposition rates in a smaller silicon area, while dichlorosilane shows the opposite trend. Flowing silane and dichlorosilane simultaneously during deposition results in a similar deposition rate independent of exposed silicon area. Decreasing hydrogen chloride partial pressure is found to improve the loading effect for both the silane- and dichlorosilane-based process for a small active window of about 0.01 μm 2 . The results point to the importance of availability of the adsorbed species on the active silicon windows when their size is below 0.04 μm 2 .