Deep Level Transient Spectroscopy of Bulk Traps and Interface States in Si MOS Diodes

Abstract

Deep-leve transient spectroscopy (DLTS) of bulk traps and interface states in Si MOS diodes are theoretically studied and energy levels, capture cross-sections and spatial and energy density distributions of majority-carrier traps are measured. In P+-implanted unannealed MOS diodes, four bulk traps are measured at Ec-0.18 eV, Ec-0.20 eV, Ec-0.31 eV and Ec-0.45 eV. Their spatial distributions are found to be the same among them within experimental error and thought to be corresponding to the distribution of implanted ions qualitatively. Bulk traps are distinguished from interface states experimentally. The capture cross-section of interface states in non-implanted MOS diodes are measured to be of the order of 10-16 cm2 in the energy range of Ec-0.15 eV to Ec-0.30 eV. The interface state density measured with DLTS is found to be in a reasonable agreement with those detetmined by other methods.