The diffusion constant for Cu in Si, at temperature 1394°C is larger than that of Ge in Si by a factor of 3.58 × 10⁶. If, after a certain time, Ge diffuses an average distance of 1 ìm, how far on average does Cu diffuse during the same time interval?

Question

Quizplus · Accepted Answer

The diffusion distance is proportional to the square root of the diffusion constant. If Ge diffuses 1 µm, Cu, with a diffusion constant 3.58 × 10^6 times larger, will diffuse √(3.58 × 10^6) times further, which is approximately 1.89 mm.

The Diffusion Constant for Cu in Si, at Temperature 1394°C