Electronic Defect Levels Research Articles

Deep-level traps in low-dose boron-implanted and low-temperature annealed silicon

The electronic defect levels in low-dose (1–8×1012 cm−2) B-implanted Si after annealing at 550 °C are measured by the deep level transient spectroscopy method. The defects, which distribute in accordance with the B profile, are assigned to interstitial- and vacancy-boron complexes; Ev +0.27 and Ev +0.43 eV, and Ev +0.47 eV, respectively. In contrast with these defects, a uniform distribution in the implanted layer is observed for Ev +0.56 eV, which is assigned to a divacancy and/or vacancy cluster. Other defects of which the energy levels are very close to those of interstitial- and vacancy-oxygen complexes are also observed.

Deep levels in scanned electron-beam annealed silicon

Electronic defect levels in scanned electron-beam annealed (SEBA) silicon have been measured by deep-level transient spectroscopy. In As+-implanted p-n junctions, hole-trap densities in the 1013-cm−3 range have been achieved with the dominant levels energetically situated for inefficient charge generation and recombination. In Schottky diodes on unimplanted silicon, SEBA-induced electron traps have been detected with principal levels at Ec−0.19 eV and Ec−0.44 eV; the defect densities decrease exponentially with distance from the beam-annealed surface. Both levels are ascribed to vacancy-impurity complexes (e.g., the 0.44-eV level identifies the P-V center), and a simple vacancy-diffusion model is proposed to explain the defect distributions.

Electronic defect levels in self-implanted cw laser-annealed silicon

Electronic defect levels in self-implanted cw Ar-laser-annealed silicon have been measured by deep-level transient spectroscopy. The electron emission spectrum is dominated by two levels near the middle of the silicon forbidden energy band with activation energies of ∼0.49 and 0.56 eV. These levels can be spatially resolved in the depletion layer of Schottky diodes due to a more rapid decrease with distance in the density of the shallower level. In samples receiving a 450 °C furnace anneal (after laser irradiation) an additional level appears at 0.28 eV; the defect density is shown to decrease monotonically with depth into the silicon substrate.