Diffusion of silicon in germanium

We present experimental results of the diffusion of silicon in germanium over the temperature range from 550 to 900 degrees C. The diffusion of silicon was measured with Secondary Ion Mass Spectrometry (SIMS) from a buried layer of Si within a Molecular Beam Epitaxy (MBE) grown epitaxial Ge layer on a Ge substrate. A 50 run thick SiO2 cap was deposited by CVD at 450 degrees C on samples for measurements above 700 degrees C to maintain the integrity of the Ge surface at higher temperatures. From the experiments, the activation energy, Q, and diffusion pre-factor, D-o, for Si diffusion in Ge were determined to be 3.32 eV and 38 cm(2)/s, respectively. The results from this work are compared critically to previous measurements of the diffusion coefficient of Si in Ge that relied on surface [I] or implanted [2, 3] Si sources, in an attempt to obtain consistency.