Selective Epitaxial Si:P Film for nMOSFET Application: High Phosphorous Concentration and High Tensile Strain

Abstract

An in-situ heavily phosphorous doped selective epitaxial Si:P process was developed to reduce the source/drain contact resistance in the scaled-down 2D and 3D nMOSFET devices. The phosphorous concentration in as-deposited Si:P epitaxial films is >1×1021 at/cc. Most of phosphorous atoms contribute to the in-film tensile strain that is comparable to Si:CP epitaxial film (with >1 at% Csub) for nMOSFETs. High-resolution XRD data and cross sectional TEM images demonstrated high quality epitaxial Si:P film grown on differently orientated substrates and planar/fin structures. Furthermore, phosphorous atoms in Si:P films can be highly activated, resulting in a low resistivity of ~0.3 mOhm-cm, by the milli-second anneal treatment without the loss of phosphorous concentration and tensile strain.