DLTS AS A LOCAL PROBE OF CONCENTRATION AND DEPTH OF TRAP LEVELS

Abstract

Complementarity of the capacitance and charge deep level transient spectroscopy (DLTS) is the idea which led us to an advanced method for profiling trap levels in semiconductors. This unifying approach to the space-charge spectroscopy, on grounds of applying the small-amplitude-filling pulse mode and evaluating the trapped charge balance, allows one to implement it in practice while using currently available instrumentation. A simple formalism is sufficient to obtain the demanded trap level depth. The usefulness of this method is demonstrated on bulk traps found in two different metal-insulator-semiconductor (MIS) capacitors. We propose also a new experimental technique providing the option of a direct determination of the trap depth from a single temperature scan. In addition, we found an expression for the relative detection sensitivity of the capacitance DLTS and justified quantitatively the earlier reported improved relative sensitivity of the charge transient spectroscopy.