Atomic Layer Deposited Al[sub 2]O[sub 3] as Characterized Reference Samples for Nanolayer Metrology

Plasma assisted Atomic Layer Deposition Al2O3 samples were studied using an approach of complementary metrology using Ellipsometry, X‐Ray Reflectivity, Atomic Force Microscopy, and Total Reflection X‐Ray Fluorescence. For modeling the samples, an interfacial rough SiO2 layer has to be assumed. The excellent linearity of the ALD process was used to cross check Ellipsometry and X‐Ray Reflectivity. In contrast to Ellipsometry, X‐Ray Reflectivity showed a residual surface layer, identified as chlorine contaminated layer by TXRF. The samples are shown to be ideal candidates for calibration of X‐ray fluorescence as the Al signal linearly depends on the film thickness or ALD cycles. Furthermore, the impact of self‐absorption of thick layers for TXRF was shown by the samples.