Investigation of Process Parameters on the Properties of Selective Epitaxial Growth SiGe Structure

Abstract

This work presents the effect of process parameters such as substrate condition, flow rate of precursors and dopant on selective epitaxial growth (SEG) of Si1-XGeX layer in recessed source and drain (S/D) regions of pMOSFET structure. It was observed that the growth rate of SEG Si1-XGeX on patterned wafer was slightly less than that of Si1-XGeX 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 Si1-XGeX 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 Si1-XGeX does not affect the channel strain.