Regensburg 2010 – wissenschaftliches Programm
DS 24.5: Vortrag
Mittwoch, 24. März 2010, 12:15–12:30, H8
In-situ EELS and UPS measurements on HfO2 ALD layers — •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-situ cycle-by-cycle (up to 10 cycles) investigations of the HfO2 ALD process using the methods of EELS and UPS.
We used TDMA-Hf as a precursor and p-type Si wafer with natural oxide as the substrate. The EELS measurements were done with a primary energy of 52,5 eV and the UPS measurements with He I (21,218 eV).
The change in the onset of the loss function is readily observed. Already after two cycles the value approach to the bulk value of HfO2. Upon ALD growth there is a remarkable decrease in the intensity of states within the gap. They are rather smooth and saturate after 10 cycles. With UPS we follow the variation of the VB onset and changes in the secondary electron onset. We summarize our data in a band diagram not based on bulk values but on cycle dependent quantities.
With these cycle-by-cycle experiments we study the initial growth of HfO2 especially in the very first cycles.
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