Raman Spectra of Silicon/Germanium Alloy Thin Films Based on Porous Silicon

Regularities of composition changes of silicon/germanium alloy thin films formed on a single-crystalline silicon substrate by electrochemical deposition of germanium into a porous silicon matrix with subsequent rapid thermal annealing (RTA) at temperatures of 750–950°C are studied. An analysis of the samples by Raman spectroscopy showed that an increase of the RTA temperature leads to a decrease in the germanium concentration in the formed film. A decrease of the RTA duration at a given temperature makes it possible to obtain films with a higher germanium concentration and to control the composition of thin silicon/germanium alloy films formed by changing the RTA temperature and duration. The obtained results on controlling the composition of silicon/germanium alloy films can be used to create functional electronic devices, thermoelectric power converters, and optoelectronic devices.