Optical Characterization Methods for Identifying Charge Trapping States in Thin Dielectric Films

Abstract

Thin film characterization methods are pushing the development of new applications beyond the standard measurements of thickness and composition and towards a complete understanding of the physical, optical, and electrical properties at the atomic scale. One of many important aspects is characterizing the electrical quality of the gate dielectric film with respect to charge trapping and leakage currents. This has conventionally been done with post‐processing electrical measurements, which deliver results that may be complicated by subsequent process steps and thermal treatments. A need to non‐invasively probe the film early in processing, as well as an economic drive to extend the capabilities of existing in‐line platforms, has led us to explore using optical methods for characterizing charge trap centers in dielectric films. In this work, we explore the capability of using spectroscopic ellipsometry as a method of identifying charge trapping states in the Si/SiO2/high‐κ gate stack system. We briefly revi...