The electrical properties of zinc in silicon

Electrically active deep levels related to zinc in silicon are investigated in n- and p-type silicon using Deep-Level Transient Fourier Spectroscopy (DLTFS) measurements. While in n-type silicon a level at E_C–0.49 eV is observed, the main zinc-related levels in p-type silicon are determined to be E_V+0.27 eV and E_V+0.60 eV. The latter are associated with zinc situated on regular silicon lattice sites. The emission rate of these centers exhibits a field dependence which cannot be quantitatively explained with the Poole-Frenkel model. On the other hand, a shallow level at E_V+0.09 eV is observed only in boron-doped silicon which may be related to a zinc-boron complex. Other zinc-related levels are found at E_V+0.23 eV and E_V+0.33 eV, their concentration depending on that of zinc on substitutional sites. In addition, the evaluation of depth profiles and the analysis of the field dependence of the emission rate based on the DLTFS method is presented.