The structure of gold silicide in thin Au/Si films

Metastable phase formation in the Au-Si system via ultrafast nanocalorimetry

“…Notice the different extinctions between the first and the second Laue zones, showing a b-center in the a-c plane. These values are close to those reported for the orthorhombic and surface structures in other studies 16,[40][41][42] after correction for thermal expansion (see Table I). The data reported by Shpyrko 16 for 2D surface freezing on liquid Au-Si alloy were obtained at 360 C; thus, adjustment for Two caloric curves from day 0 (black) and day 2 (red) are overlapped and are almost identical.…”

“…20)) form by quenching large bulk liquid samples yielding large particles $40 000 nm. In contrast, all the previous work 40, 41 for d 1 and work here show small sample sizes in the 15-100 nm range. It is possible that d 1 is actually the first phase formed for all alloys but it goes undetected because of the miniscule amounts present at the initial stages of solidification-d 1 may act as the nucleation seed for subsequent formation of other alloys.…”

“…d 1 may not be a line-compound since there is appreciable range in the reported lattice con-stants (see Table I) (a:5%, b:7%, c:4%) and their volume (DV:17%). 40,41 Given that the presence of Au is important to the formation of d 1 , we explore the melting/solidification using heating/cooling data (Fig. 4) and the boundaries of d 1 formation over the entire composition range (Fig.…”

Structural phase transitions in Au thin films on Si (110): An in situ temperature dependent transmission electron microscopy study

“…While comparing them with the reported phases these spacings match with several phases like Au 2 Si, Au 3 Si, Au 7 Si and Au 4 Si. Many diffraction patterns of gold silicides have been presented over the years [23][24][25][26][27][28]. Hultman et al rightly pointed out that when comparing the observed data with reported phases of gold silicides, surprisingly there is a good agreement between the d values for at least 8-12 strongest reflections of all the alloys [29].…”

Surface structure of the liquidAu72Ge28eutectic phase: X-ray reflectivity

“…There are no known stable intermetallic Au-Si phases that resemble the lattice constants for the 2D AuSi 2 phase; however, there are similarities to phases that have been observed in thin metastable solid Au-Si films. [22][23][24] At the present time there is no theoretical explanation for the Au-Si surface effect; however, it is reasonable to speculate that it might arise from the relatively strong covalency between Au and Si. In the absence of reliable theoretical guidance it is natural to ask whether the Au-Ge system exhibits a surface structure that is similar to that found in Au-Si.…”