Multiple Oscillators of Optical Dispersion, Continuous Cody Lorentz Model

摘要

A method and system for monitoring band structure properties early in a semiconductor fabrication process and predicting electrical properties of a sample are presented herein. High throughput spectrometers generate spectral response data from semiconductor wafers. In one example, the measured optical dispersion is characterized by a Gaussian oscillator, a continuous Cody Lorentz model. The measurement results are used to monitor band structure properties, including charge trap centers, exciton states, defects such as phonon modes, and band gaps in high-K dielectric layers and embedded nanostructures. The Gaussian oscillator, continuous Cody Lorentz model can be generalized to include any number of defect levels. Also, the shape of the absorption defect peak may be expressed by a Lorentz function, a Gaussian function, or both. These models represent experimental results quickly and accurately in a physically meaningful way. The model parameter values can subsequently be used to gain insight and control over the manufacturing process.