Ab-initio calculations to predict stress effects on boron solubility in silicon

Stress effects on dopant diffusion and activation are of critical interest in current and future CMOS devices. Since experiments are very difficult to perform, we utilized ab-initio calculations to predict the effect of stress on B solubility. We find strongly enhanced solubility under compressive biaxial stress, whereas tensile biaxial stress leads to a reduction. In contrast to other work the enhancement/reduction is primarily due to the size effect of substitutional B. We compared our calculated B strain relaxation effect with various x-ray diffraction data, which shows excellent agreement. Measurements in different SiGe alloys also support our predictions.