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DS: Fachverband Dünne Schichten
DS 12: Layer Deposition Processes
DS 12.1: Vortrag
Montag, 14. März 2011, 17:15–17:30, GER 38
A growth model for the HfO2 ALD process — •Marcel Michling, Massimo Tallarida, Krzysztof Kolanek, and Dieter Schmeißer — Brandenburgische Technische Universität Cottbus, Angewandte Physik / Sensorik, K.-Wachsmann-Allee 1, 03046 Cottbus
In this contribution we report on our in-situ2 cycle-by-cycle (up to the 25 cycles) investigation of the HfO2 atomic layer deposition (ALD) process using the method of x-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS). We used Tetrakis-Dimethyl-Amino-Hafnium (TDMA-Hf) and H2O as precursors and p-type Si wafer with native oxide as a substrate. The XPS measurements were carried out at BESSY II in Berlin with primary energies of 150 eV and 640 eV and the EELS measurements were done with a primary energy of 50 eV. We measured the O1s, Si2p core level and the valence band including the Hf 4f core level. From the Hf4f to Si2p ratios taken at each energy we developed a growth model for the first monolayer and for the following layers too. From our data we conclude, that in the first monolayer up to the fourth ALD cycle an island growth occurs. The height of these islands is about 0,5nm. After the first monolayer is completed, a layer- by-layer growth can be expected. In order to proof this observation we have simulated the Hf/Si ratio for different excitation energies and found a very good agreement with our measurement data. The EELS data especially the evaluation of the loss function onset confirm our growth model.