In situ measurements of the atomic layer deposition of high-k dielectrics by atomic force microscope for advanced microsystems

摘要

We investigated in situ the atomic layer deposition (ALD) of high-k dielectrics for advanced microsystems by ultra high vacuum (UHV) atomic force microscope (AFM). With our equipment we examined the surface topography of the substrate and the thin high-k films without breaking the vacuum and therefore without contaminating the sample with external agents. Following the full analysis of the Si(001)/SiO_2 substrates we started the ALD process. After each ALD cycle using tetrakis-dimethyl-amido-Hf (TDMAHf), and H_2O as precursors, we studied the relation between the film growth and the root mean square surface roughness, surface fractal dimension and correlation length. Additional information about the ALD was extracted from the statistical description of the surface by the height histogram together with the surface skewness and kurtosis parameters. The in situ studies of the ALD process with the UHV/AFM system were correlated with the experiments performed by means of synchrotron radiation photoelectron spectroscopy for understanding the fundamental properties of the ALD of high-k thin films on Si(001)/SiO_2 substrates.