Investigation of process parameters on the properties of selective epitaxial growth SiGe structure

This work presents the effect of process parameters such as substrate condition, flow rate of precursors and dopant on selective epitaxial growth (SEG) of Si_1-xGe_x layer in recessed source and drain (S/D) regions of pMOSFET structure. It was observed that the growth rate of SEG Si_1-xGe_x on patterned wafer was slightly less than that of Si_1-xGe_x on bare wafer as GeH₄ flow rate increased. And an in-situ boron-doped SiGe layer exhibits lower growth rate and Ge content than intrinsic SiGe layer due to a decrease of GeH₄ partial pressure. Nano beam electron diffraction (NBD), which is an efficient method to measure induced compressive strain in Si channel, is applied on both intrinsic and in-situ boron doped Si_1-xGe_x layers with a different Ge content. NBD patterns confirmed that higher Ge concentration introduces more strain in the channel region and in-situ boron doping of Si _1-xGe_x does not affect the channel strain.