Ultrathin dielectric capping layers are a prominent route for threshold voltage control in advanced Si devices. In this work the position of an Al2O3 layer inside a HfO2-based stack is systematically varied and investigated following a low and a high temperature anneal. Electrical results are compared with a sub-nanometer resolution materials characterization, showing a diffusion of Al to the bottom HfO2 interface. A correlation is found between the presence of Al at the bottom interface and a flatband voltage increase. Based on these findings, we propose to use the position of the Al2O3 for fine-tuning the threshold voltage.
Investigation of the band offsets caused by thin Al2O3 layers in HfO2 based Si metal oxide semiconductor devices
Lior Kornblum, Boris Meyler, Catherine Cytermann, Svetlana Yofis, Joseph Salzman, Moshe Eizenberg; Investigation of the band offsets caused by thin Al2O3 layers in HfO2 based Si metal oxide semiconductor devices. Appl. Phys. Lett. 6 February 2012; 100 (6): 062907. https://doi.org/10.1063/1.3684939
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