STRUCTURE AND THERMAL CONDUCTIVITY OF THIN FILMS OF THE Si1-xGexВ ALLOY FORMED BY ELECTROCHEMICAL DEPOSITION OF GERMANIUM INTO POROUS SILICON
D.L. Goroshko1, I.M. Gavrilin2, A.A. Dronov2, O.A. Goroshko1, L.S. Volkova3
1Institute of Automation and Control Processes, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
2National Research University of Electronic Technology (MIET), Moscow, Russia
3Institute of Nanotechnology of Microelectronics, Russian Academy of Sciences, Moscow, Russia
Keywords: SiGe alloy, thermal conductivity, electrochemical deposition of germanium, porous silicon
Abstract
Solid and porous films of the Si 1-xGex alloys with a germanium content of about 40% and a thickness of 3-4 μm, formed on single-crystal silicon by electrochemical deposition of germanium into a porous silicon matrix followed by rapid thermal annealing at a temperature of 950 °C, are studied by Raman spectroscopy, optical spectroscopy, and scanning electron microscopy. Based on the Raman spectra taken in the Stokes and anti-Stokes frequency regions, using Boltzmann statistics and the Fourier thermal conductivity law, the thermal conductivity of the films is determined, which is found to be 7-9 and 3-6 W/(m×K) for a continuous and porous film, respectively. The low thermal conductivity of the porous film is explained by additional phonon scattering from the developed pore surface. The prospect of using such films in thermoelectric converters is ensured by the simplicity and scalability of the method for manufacturing the alloy, as well as its low thermal conductivity.
|
