Electron Holography Characterization of Epitaxial Si(P+)/Si(B-) Substrate Structures

Epitaxial growth of n-type Silicon is one of the key pathways to enable semiconductor device scaling. Such epitaxial growth requires a crystalline Si atomic template. The interface between Si(P+)/Si(B-) substrate is not very well understood, particularly the stability and effect of the carriers at these interfaces. Si:P epitaxial thin films were grown on top of Si:B- substrate using single-wafer chemical vapor deposition (CVD) technique, with different dopant concentration. Basic interfacial characterization was done using high resolution X-Ray diffraction (HRXRD), dynamic secondary ion mass spectroscopy (D-SIMS) and strain measurements. The characterization showed presence of substitutional doping resulting in tensile lattice strain of the epitaxial Si:P film. Electron holography measurements were used to characterize the overall interfacial charge, indicating the presence of static and dynamic built-in voltage across the stack. We analyze the phase shift closely to understand the contribution of built-in voltage and mean inner potential (MIP) and their respective dependence on Phosphorus doping.