Measurements were made of the lower yield point of undoped float-zone material at temperatures of between 800 and 1300C. It was found that, above about 1050C, there were marked deviations from the well-known low-temperature behavior; thus establishing a further deformation regime which was characterized by an activation energy of 4.1eV. This effect depended upon the as-grown dislocation density, but not upon the ambient conditions during deformation. It was tentatively assumed that it reflected the change in the self-diffusion mechanism which was typical of this material at high temperatures.

A Regime of the Yield Point of Silicon at High Temperatures H.Siethoff, H.G.Brion, W.Schröter: Applied Physics Letters, 1999, 75[9], 1234-6