Surface treatment for high-quality Al2O3 and HfO2 layers deposited on HF-dipped surface by atomic layer deposition

Al2O3 and HfO2 thin layers were deposited on either 0.7-nm chemical SiO2 surface layers, HF-dipped Si surfaces or on HF-dipped Si surfaces with an innovative Cl-2 surface treatment. This chemical treatment leads to the formation of one mono-layer of -OH groups on the silicon surface without any SiOx growth. Thicknesses, composition, and structure of the high-k layers as well as the nature of their interfaces with silicon were studied using spectrometric ellipsometry, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). While deposition on a HF-dipped Si surface led to a nucleation retardation and to a 3-dimensional growth mode, high-quality, uniform Al2O3 layers were obtained on a Cl-2-treated Si surface. XPS and ATR analyses showed a very small SiOx regrowth, less than 0.26 nm during deposition. (C) 2003 Kluwer Academic Publishers.