Selective Growth of B- and C-Doped SiGe Layers in Unprocessed and Recessed Si Openings for p-type Metal-Oxide-Semiconductor Field-Effect Transistors Application

This work presents the pattern dependency of the selective epitaxial growth of boron- and carbon-doped SiGe layers in recessed and unprocessed openings. The layer profile is dependent on deposition time, chip layout, and growth parameters. Carbon and boron doping compensates for the strain in SiGe layers, and when both dopants are introduced, the strain reduction is additive. The incorporation of boron and carbon in the SiGe matrix is a competitive action. The concentration of carbon decreases, whereas the boron amount increases in SiGe layers with higher Ge content. In recessed openings, the Ge content is independent of the recess depth. The strain amount in the grown layers is graded vertically, which is due to the thickness of the epilayer exceeding the critical thickness.