Electrical characterization of majority carrier traps in electron irradiated epitaxial N-type Si

Abstract

Epitaxial p+/n–/n+ silicon diodes have been irradiated with 6 MeV electrons to a dose of 1014 cm−2, and isochronal and isothermal annealings at the temperatures 325 – 360 C has been performed. The reaction kinetics of VO, V2O and VOH is studied and compared to the corresponding defect behavior in diffusion oxygenated float zone (DOFZ) and magnetic Czochralski (MCz). VO and V2O is found to mainly dissociate, in correspondance with studies in DOFZ and MCz, but a fraction of VO also anneals by production of VOH as found by depth profiling. Depth profiling also suggests that VOH subsequently disappears through the generation of VOH2. Modeling is performed which confirms these conclusions.

The growth rate of VOH, with c0 = 3 × 1013 s−1, is further argued to be close to the dissociation rate of a near–surface hydrogen complex HZ because of the high diffusivity of H. Furthermore, the loss of an unidentified defect labeled E(170 K) is proportional to the growth of VOH, and the ratio approaches unity at 360 C. Ea and c0 is also identical for the decay of E(170 K) and the growth of VOH. Thus, the decay of E(170 K) is believed to be because of the reaction E(170 K) + Z ! inactive complex, where the diffusivity of Z is large. The growth of a second unidentified defect labeled E(198 K) is proportional to the loss of V2O, with a ratio of 0.14 ± 0.03.