Deep‐Level Transient Spectroscopy

Abstract

AbstractDefects are responsible for many different characteristic properties of a semiconductor. They play a critical role in determining the viability of a given material for device applications. The identification and control of defects have always been among the most important and crucial tasks in materials and electronic device development. The performance and reliability of devices can be significantly affected by only minute concentrations of undesirable defects. Since the determination of the type and quality of defects in a material depends on the sensitivity of a characterization technique, the challenge in materials characterization has been to develop detection methods with improved sensitivity.Deep‐level transient spectroscopy (DLTS) probes the temperature dependence of the charge carriers escaping from trapping centers formed by point defects in the material. This technique is able to characterize each type of trapping center by providing the activation energy of the defect level relative to one of the energy band edges and the capture cross‐section of the traps. It can also be used to compute the concentration and depth profile of the trapping centers.The spectroscopic nature of DLTS is a key feature that provides both convenience and sensitivity.Deep‐level transient spectroscopy has been widely used for many different semiconductors. This technique has distinguished itself in contributing to the resolution of many defect‐related problems in several technologically important semiconductors such as silicon, the Group III to V and II to VI compounds, and alloys. Many variations of basic DLTS have also been developed for improved sensitivity and for more specialized applications in device structures different from the normalp‐nor Schottky barrier diodes.Deep‐level transient spectroscopy is not able to determine the chemistry or the origin of a defect. Deep‐level transient spectroscopy data should therefore be used in conjunction with other techniques. A successful study of defects requires the concerted efforts of many researchers using various characterization techniques in order to derive a more accurate and consistent picture of the defect structure of a given material.