Ultrasonic influence on point defects in a dislocation free Si

Ultrasound (US) influence on dislocation free (DF) silicon is investigated. Ultrasonic waves attenuation (/spl alpha/), mobility of intentionally induced superficial dislocations, and minority carriers diffusion length (L) are measured from a dislocation free Cz-Si as a function of US amplitude. The general results consist of some changes in the properties under study that takes place in a threshold way. Under US deformation S>10/sup -5/ attenuation a becomes nonlinear, dislocation mobility and so microplasticity vary significantly, and L increases up to 2 times. US in DF Cz-Si can effectively interact with a system of point defects. The acoustostimulated changes in DF Cz-Si properties under study are connected to ultrasonically activated transformations in a system of crystal point defects and their complexes. We find there are two thresholds of US deformation: S/sub 1//spl sim/10/sup -6/ and S/sub 2//spl sim/10/sup -5/. Under deformation S