@inproceedings{AlbertonCorreaBrizziTallaridaetal., author = {Alberton Corr{\^e}a, Silma and Brizzi, Simone and Tallarida, Massimo and Schmeißer, Dieter}, title = {Charging effect in HfO2 films deposited on SiO2/Si by atomic layer deposition}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, abstract = {Thin films of hafnium oxide (HfO2) deposited by atomic layer deposition (ALD) have been studied extensively as a high-k replacement for the SiO2 gate in field effect transistors. The use of ALD process allows one to grow homogeneous thin films at low temperatures with a precise control of thickness [1]. Some important electrical considerations for the application of a high-k dielectric include the presence of fixed charge (Qf) and charge trapping in the dielectric. For instance, in the case of Al2O3 thin films deposited on Si, the thickness of the interfacial SiO2 layer was identified as a key fundamental parameter determining Qf [2]. A similar trend can be also expected in HfO2/Si structures. Therefore, in this work, we proposed an in situ evaluation of photon induced charge trapping in HfO2 films deposited on SiO2/Si structures. For that, tetrakis-di-methyl-amino-hafnium (TDMAHf) and H2O were employed as precursors to deposit HfO2 films on SiO2/Si samples with variable thickness of the SiO2 interlayer. Measurements were performed by Synchrotron Radiation Photoemission Spectroscopy (SR-PES). Results indicated that the charging process is dependent on the thickness of the SiO2 interlayer and on the quality of the HfO2 film. [1] M. Leskel{\"a} and M. Ritala, Thin Solid Films 409, 138 (2002). [2] G. Dingemans et al., J. Appl. Phys. 110, 093715 (2011).}, language = {en} } @inproceedings{AlbertonCorreaBrizziTallaridaetal., author = {Alberton Corr{\^e}a, Silma and Brizzi, Simone and Tallarida, Massimo and Schmeißer, Dieter}, title = {Spectroscopic investigation of the electronic structure of HfO2 thin films}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 211}, abstract = {HfO2 is of current interest as a material for memristive and ferroelectric devices. In this work, we used spectroscopic techniques to evaluate the electronic structure and defects mechanisms in thin HfO2 films deposited by atomic layer deposition and by metal-organic chemical vapour deposition. The partial density of states for the valence and the conduction bands was determined by the detailed analysis of the O1s resonance profile by resonant photoelectron spectroscopy. From the relative contributions we find a CNL 6.5 eV referred to Evac. We also find that the positions of valence band maximum and conduction band minimum, the excitation range for the polaronic states and the range of charge transfer band were not influenced by the preparation conditions. All films exhibit a band gap of 6.2 eV. However, the Fermi level position was found to vary within about 1.2 eV depending on the preparation conditions, which we argue that is due to the presence of charges within the films. This explains why the position of the Fermi level depends on the individual preparation parameters.}, language = {en} } @inproceedings{RouissiBrizziAlbertonCorreaetal., author = {Rouissi, Zied and Brizzi, Simone and Alberton Corr{\^e}a, Silma and Tallarida, Massimo and Schmeißer, Dieter}, title = {Comparison of charge neutrality level of Cu/CuO/HfO2 and Si/SiO2/HfO2}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {208}, abstract = {Copper Oxide (CuO) is a promising metal oxide semiconductor, which can be used in different applications, such as catalysis, solar energy conversion, and water splitting. In this work, we use resonance photoemission spectroscopy (ResPES) to analyse the electronics properties of HfO2 films deposited on Cu/CuO and Si/SiO2. For that, we deposited 10 cycles of HfO2 by atomic layer deposition (ALD) on Cu/CuO and Si/SiO2 samples and investigated the density states for the valence and conduction bands which were determined by the detailed analysis of the O1s resonance profile obtained by ResPES. We compared the positions of valence band maximum and conduction band minimum, the excitation range for the polaronic states and the range of charge transfer band in Cu/CuO/HfO2 and Si/SiO2/HfO2. Also, we determined the band gap and the charge neutrality level (CNL).}, language = {en} }