Authors: F. Yang
Affilation: University of Rochester, United States
Pages: 430 - 433
Keywords: one-dimensional diffusion, stresses, electric field, wafers, MEMS
The diffusion-induced stresses in silicon wafers were studied. The effect of local electric field on dopant diffusion was considered in the diffusion equation. Only one-dimension problem with a constant surface dopant concentration was investigated. The closed form solutions of stresses and expansion of the wafer arising from dopant diffusion are obtained on the basis of linear elastic theory. The results show that the wafer surface is always under compression, while at the wafer center the stress is tensile. The maximum compressive stress is at the surface of the wafer at the initial time, which is independent of the local electric field. The stress at the wafer surface decreases with time. It increases with local electric field and gradually approach to zero with time.