X-ray reflectometry and x-ray fluorescence monitoring of the atomic layer deposition process for high-k gate dielectrics

Abstract

This work introduces inline x-ray fluorescence (XRF) and x-ray reflectometry (XRR) metrology tools to aid the process development of atomic layer deposition on high-k dielectric films. In this approach, XRR monitors the deposition rate of the thickness and identifies the transition from the three-dimensional to the two-dimensional growth regime. XRF is used to monitor the atomic deposition rate. The interpretation of XRR result is verified with transmission electron microscopy (TEM) and Auger electron spectroscopy. Unlike the conventional approach using Rutherford backscattering to monitor deposition rate and TEM to monitor thickness, this proposed scheme is noninvasive and does not require any sample preparation. In addition, the inline approach prevents exposing the film to a nonproduction grade environment and avoids the potential growth of the high-k interface or degradation of the film during the measurement.