Influence of in-situ Boron Doping on the Surface Roughening of SiGe:B Films

Selective epitaxial growth of B-doped SiGe (SiGe:B) films is one of the key techniques for the embedded SiGe (e-SiGe) structure for high-performance pMOSFETs. Both the high Ge composition and the high B-doping concentration are desirable for increasing the stress in the channel region and decreasing the series resistance in the source/drain region. However, increasing Ge composition and B concentration may lead to defects in the epitaxial SiGe:B layer and thus to the roughening of the surface of the films. In this work, influence of B doping on the surface roughness and the roughening process in SiGe:B epitaxial films are examined.