Deep Level Characterization Improved by Laplace Charge Transient Spectroscopy

Shumpei Koike, Kazuo Uchida, Shinji Nozaki

Deep-level transient spectroscopy (DLTS) has been widely used to electrically characterize the defects in semiconductors. The DLTS spectrum obtained by the rate-window analysis often shows a peak resulting from a transient signal made of two or more exponential signals. In such a case, the energies of the defects responsible for the transient are closely spaced together. The analysis of the transient signal by the inverse Laplace transform is able to resolve a single energy obtained by the rate-window analysis into multiple energies. The charge transient signal is more favored for the inverse Laplace transform than for the capacitance transient signal because the data can be immediately obtained after the pulse by the charge transient spectroscopy (QTS). Using a simulation, the Laplace charge transient spectroscopy has been shown to improve the deep level characterization.