Practical B and P doping via Si_xSn_yGe_(1-x-y-z)M_z quaternaries lattice matched to Ge: Structural, electrical, and strain behavior

摘要

We describe the fabrication of B and P doped SiGeSn ternaries, lattice-matched to Ge, with compositions adjusted to independently tune the band gap. These are deposited at 320-350 ℃ with superior crystallinity and morphology via in situ reactions of diborane (p-type) and designer P(SiH_3)_3 and P(GeH_3)_3 precursors (n-type). Device-level carrier concentrations in the 10~(19)-10~(20)/cm~3 range are produced yielding film resistivities and carrier mobilities comparable to those of Ge indicating negligible alloy scattering. High boron levels induce a significant and systematic contraction of the host lattice, which is compensated by an adjustment of the Sn/Si ratio in accord with a simple model based on Vegard's law, the mismatch of covalent radii of the constituents, and the absolute hydrostatic deformation potentials for the band edges.