Abstract: The science of diffusion had its beginnings in the 19th century, although the blacksmiths
and metal artisans of antiquity already used diffusion phenomena to make such objects as iron
swords and gilded bronze wares. Diffusion as a scientific discipline is based on several corner
stones. The most important ones are: (i) The continuum theory of diffusion originated from the
work of the German physiologist Adolf Fick, who was inspired by elegant experiments on diffusion
in gases and of salt in water performed by the Scotsman Thomas Graham. (ii) The Brownian
motion, observed for the first time by the British botanist Robert Brown, was interpreted decades
later by Albert Einstein and almost at the same time by the Polish physicist Marian Smoluchowski.
Their theory related the mean square displacement of atoms to the diffusion coefficient. This
provided the statistical cornerstone of diffusion and bridged the gap between mechanics and
thermodynamics. The Einstein-Smoluchowski relation was verified in tedious experiments by the
French Nobel laureate Jean Baptiste Perrin and his coworkers. (iii) The atomistics of solid-state
diffusion had to wait for the birthday of solid-state physics heralded by the experiments of the
German Nobel laureate Max von Laue. Equally important was the perception of the Russian and
German scientists Jakov Frenkel and Walter Schottky, reinforced by the experiments of the
American metallurgist Ernest Kirkendall, that point defects play an important role for properties of
crystalline substances, most notably for those controlling diffusion and the many properties that
stem from it. This paper is not meant as systematic history of diffusion. It is devoted to some major
landmarks and eminent pioneers of diffusion including also people from recent decades until today.
Authors: Hartmut Bracht, René Kube, Erwin Hüger, Harald Schmidt
Abstract: The contributions of vacancies and self-interstitials to silicon (Si) self-diffusion are a matter of debate since many years. These native defects are involved in dopant diffusion and the formation of defect clusters and thus influence many processes that take place during Si single crystal growth and the fabrication of silicon based electronic devices. Considering their relevance it is remarkable that present data about the properties of native point defects in Si are still limited and controversy. This work reports recent results on the properties of native point defects in silicon deduced from self-diffusion experiments below 850°C. The temperature dependence of silicon self-diffusion is accurately described by contributions due to vacancies and self-interstitials assuming temperature dependent vacancy properties. The concept of vacancies whose thermodynamic properties change with temperature solves the inconsistency between self-and dopant diffusion in Si but further experiments are required to verify this concept and to prove its relevance for other material systems.