Temperature Dependence of Raman Peak Shift in Single-Crystalline Silicon-Germanium

Abstract

We demonstrate the relationship between Raman shift ω and temperature T (dω/dT) of silicon-germanium (SiGe) for Si-Si, Si-Ge, and Ge-Ge vibration modes which should be useful in local temperature evaluation of SiGe devices at submicron levels. We investigated the dω/dT of single-crystalline SiGe for Si-Si, Si-Ge, and Ge-Ge vibration modes and its dependence on the Ge fraction using variable-temperature Raman spectroscopy. We clarified that the (dω/dT)s for Si-Si, Si-Ge, and Ge-Ge are fairly constant for all single-crystalline SiGe samples. Therefore, the anharmonic vibration of Si-Si, Si-Ge, and Ge-Ge modes has no Ge-fraction dependence in SiGe. The peak shifts help define the temperature on the submicron-scale surface.

Local thermal conductivity properties of a SiGe nanowire observed by laser power sweep Raman spectroscopy

“…37,38) In order to evaluate the thermal properties of SiGe NWs, the temperature of the sample was estimated using the relation of dω/dT = -0.0178 cm −1 /K for the Ge-Ge mode of SiGe alloy. 33) We consider that dω/dT has a constant value regardless of material structure, and both size and stress do not affect the temperature measurement using dω/dT of SiGe based on the previous reports on the temperature dependence of Si NW 9,30) by Raman spectroscopy. 33) Figure 4 shows the laser power-dependent temperature of SiGe NWs and Ge substrate using the Raman shift.…”

“…33) We consider that dω/dT has a constant value regardless of material structure, and both size and stress do not affect the temperature measurement using dω/dT of SiGe based on the previous reports on the temperature dependence of Si NW 9,30) by Raman spectroscopy. 33) Figure 4 shows the laser power-dependent temperature of SiGe NWs and Ge substrate using the Raman shift. As shown in Fig.…”

“…We have previously investigated the (dω/dT)s for Si-Si, Si-Ge, and Ge-Ge vibration modes over the entire Ge fraction range from single-crystalline bulk SiGe to establish precise temperature measurement in SiGe by Raman spectroscopy. 33) However, there are no reports on the evaluation of thermal transport mechanisms of the SiGe fine structure by the (dω/dT)s. In this study, we performed detailed experiments on SiGe NWs with different wire widths using laser power sweep Raman spectroscopy 34) and the dω/dT value of SiGe in order to figure out the correlation between the thermal properties and Ge-rich SiGe NWs structure.…”

Determination of Ge-fraction-shift coefficients for Raman spectroscopy in all vibration modes investigated by single-crystalline bulk SiGe and its application to strain evaluation in SiGe film grown on substrate

“…In addition, XRD confirmed that the singlecrystalline bulk SiGe samples were in strain-free states. 25,26) In other words, the obtained lattice parameters of bulk SiGe samples are expressed by the values reported by Dismukes et al 7) We used a Raman spectrometer with a focal length of 2000 mm and high-wavenumber resolution 27) to obtain precise spectral shapes of Raman spectra of SiGe. There were 1800 mm −1 grating grooves (for the Si-Si and Si-Ge modes) and 2400 mm −1 (for the Ge-Ge mode).…”