Phase formation in Cu-Si and Cu-Ge

Abstract

Phase formation and growth kinetics have been investigated with lateral diffusion couples in Cu-Si and Cu-Ge systems. Analytical electron microscopy was used to determine the crystal structures and chemical compositions of the growing phases. CusSi is found to be the dominant phase in the Cu-Si system. The growth of the silicide follows a (time) 1'2 dependence with an activation energy of 0.95 eV in the temperature range of 200-260 "C. Cu3Ge is the only phase observed in Cu-Ge lateral diffusion couples with its length up to 20 ,um. The growth of CusGe is a diffusion controlled process at a rate similar to that of Cu$i. The activation energy of CusGe growth is 0.94 eV at 200-420 "C. In Cu-silicide or Cugermanide formation, Cu appears to be the dominant diffusing species.

Molecular view of copper deposition chemistry: (Hexafluoroacetylacetonate)Cu(vinyltrimethylsilane) on a Si(100)-2×1 surface

“…Barely noticeable AES signature for copper is also observed. Note that copper diffusion into silicon is facile with an activation energy for diffusion less than 1 eV [22]. Decomposition was previously observed upon annealing on TiN [23], and Cu surfaces [24] but in the present study the diffusion process precludes from making quantitative observations based solely on AES.…”

Structure, Growth Kinetics, and Ledge Flow during Vapor−Solid−Solid Growth of Copper-Catalyzed Silicon Nanowires

“…34 An estimate of diffusion times within the catalyst suggests that wire growth should indeed be limited by disilane dissociation rather than by diffusion through the bulk of the catalyst. The activation energy of interdiffusion of Cu and Si in Cu 3 Si, 0.95 eV, 35 is much lower than that of Si self-diffusion (>4 eV) 36 and that of diffusion of Si at the interface between Cu 3 Si and Si (2.5 eV). 37 As a result, mass transfer of Si and Cu should be dominated by interdiffusion within the catalyst.…”

Microstructural and electrical properties of Cu-germanide formed on p-type Ge wafer

“…However, despite the prominent features of Cugermanide, reports on its material properties are limited. Hong et al [14], investigating the phase formation and growth kinetics with lateral diffusion couples in CueGe system, reported the diffusion controlled formation of the Cu 3 Ge. Lai et al [20] found that annealing process at the temperatures in the range of 150e500 C led to the formation of polycrystalline Cu 3 Ge film which underwent agglomeration at 550 C. Similarly, Elbaum et al [15] and Gaudet et al [16] showed that as a result of reaction between Cu and Ge, the Cu 3 Ge thin film with a low resistivity was formed at relatively low temperature.…”