Characterization of high-k gate dielectric and metal gate electrode semiconductor samples with a total reflection X-ray fluorescence spectrometer

The versatility of a total reflection X-ray fluorescence (TXRF) spectrometer in the analysis of semiconductor samples will be demonstrated. While TXRF has a well-established place in trace metals analysis on silicon wafers, the practice of characterizing new films with TXRF is not routine in the semiconductor industry. In this paper, we will examine the monitoring of high-k film growth on silicon wafers by TXRF. We will show that a linear relationship between cycles of film deposition and TXRF signal is possible with proper analytical conditions. This signal can be converted to film thickness by normalizing to cross-sectional measurement from transmission electron microscopy (TEM). Information about the interface between the deposited high-k layer and the silicon substrate can also be determined from TXRF data. Secondary ion mass spectrometry data of a chlorine species at the interface of the high-k and silicon were collaborated with TXRF data. Critical angle measurements were taken on ruthenium and ruthenium dioxide films to extract physical characteristics and these results were compared to those from other techniques.