Study of photocapacitance in diodes fabricated from silicon doped with vanadium
Abstract
The levels of vanadium in the band gap of n-and p-Si were determined using photocapacitance measurements. It is shown that vanadium introduces levels only in the upper half of the band gap of n-Si; these levels have ionization energies of about E c −0.21 eV, E c −0.32 eV, and E c −0.52 eV. By contrast, V levels are located both in the upper and lower halves of the p-Si band gap: E c −0.26 eV, E v +0.52 eV, E v +0.42 eV, and E v +0.31 eV. It is ascertained that the photoionization cross sections of all vanadium levels are larger for electrons than for holes. It is shown that the concentration of electrically active vanadium centers in n-and p-Si depends on both the concentration of shallow-level impurities and the time of vanadium diffusion into Si.