Annealing Effects on Polycrystalline Silicon Germanium (SiGe) Thin Films grown on Nanostructured Silicon Substrates using Thermal Evaporation Technique

Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.