Study on the annealing growth of Ge dots at high deposition rate by using magnetron sputtering technique

The 14 nm thick Ge thin films are firstly deposited on Si substrate at 350 ℃ by using the magnetron sputtering technique, then the Ge/Si dots are successfully fabricated by annealing those Ge films. According to the morphology and phonon vibration information obtained by AFM and Raman spectroscopy, the formation and evolution mechanism are studied in detail. Experimental results indicate that the amorphous Ge films have been converted to Ge dots with a density of 8.5109 cm-2 after 675 ℃ annealing for 30 min. By using Ostwald ripening theory, surface diffusion model, and calculation of the activation energy, the surface transfer and the dot formation behavior of Ge atoms can be well interpreted. Based on the fabrication technique of Ge/Si nanodots at a high deposition rate combined with the thermal annealing, we have provided a theoretical support for the experiment on self-assembled growth of Ge quantum dots.