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Advanced Electrical Characterization of Charge Trapping in MOS Transistors


The metal-oxide-semiconductor field effect transistor (MOSFET) is the basic building block of integrated circuits and stands at the heart of most modern electronic devices. It is considered a key technology and had a considerable influence on the cultural, societal, and economic development of the past decades. In light of this, it is not surprising that enormous efforts are put in the improvement of the transistors. One important aspect affecting the performance and also the reliability of these devices are atomic scale defects, inevitably introduced during manufacturing or newly created during operation. These defects possess the ability to capture electric charges and thereby affect the operation of the transistors. With the ongoing miniaturization of transistors, the impact of such defects on the device behavior grows. Effects for which these defects are responsible are among others bias-temperature instabilities (BTI), random telegraph noise (RTN) and hot carrier degradation (HCD).

With the ongoing development of MOSFETs, various characterization methods have been developed to study the wealth of effects plaguing these devices. In the last years, the miniaturization of the transistors paved the way for the development of new methods which aim at the detailed characterization of single defects. These measurements allow to verify and improve detailed models of single defects describing their atomistic nature and their charge trapping behavior. At the same time, this poses new challenges for characterization of a technology, as many such defects need to be studied to obtain the averages and distributions of the defects’ influences on the devices, which requires improvements of the experimental approaches and data processing.

This work covers the experimental characterization and theoretical description of these defects and elaborates the measurement data analysis in combination with TCAD simulation. Different characterization and simulation methods are used to study defects in three separate technologies to draw conclusions about their distributions and physical nature.