@misc{DudekLupinaKozłowskietal., author = {Dudek, Piotr T. and Lupina, Grzegorz and Kozłowski, Grzegorz and Zaumseil, Peter and Bauer, Jakob and Fursenko, Oksana and Dabrowski, Jarek Marek and Schmidt, R. and Lippert, Gunther and M{\"u}ssig, Hans-Joachim and Schr{\"o}der, Thomas and Schmeißer, Dieter and Zschech, Ehrenfried}, title = {Atomic-scale engineering of future high-k dynamic random access memory dielectrics: The example of partial Hf substitution by Ti in BaHfO3}, series = {Journal of Vacuum Science and Technology / B}, volume = {29}, journal = {Journal of Vacuum Science and Technology / B}, number = {1}, issn = {2166-2754}, language = {en} } @inproceedings{DudekLupinaKozłowskietal., author = {Dudek, Peter and Lupina, Grzegorz and Kozłowski, Grzegorz and Dabrowski, Jarek Marek and Lippert, Gunther and M{\"u}ssig, Hans-Joachim and Schmeißer, Dieter and Schroeder, Thomas}, title = {Band structure and electrical properties of MBE grown HfO2 - based alkaline earth perovskites}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 232}, abstract = {Ultra thin dielectric films (<20 nm) deposited on TiN electrodes are interesting for MIM capacitor application. High capacitance density and dielectric permittivity must be accompanied by extremely low leakage currents (10-8 A/cm2) at bias 0.5 V. To achieve such low leakage currents, high band gap and proper band alignment is required. Occupied electronic states can be probed with standard laboratory photoemission methods. Probing of unoccupied states is more challenging. Synchrotron based PES in combination with XAS forms a powerful method to study the band alignment. ASAM end station located at the U 49/2 PGM 2 beamline of BESSY II (Berlin) offers excellent conditions for performing such measurements. We investigated HfO2 - based alkaline earth perovskite - BaHfO3 with subsequent admixture of TiO2, resulting in formation of BaHf0.5Ti0.5O3 compound. The analysis of data indicates that band gap for HfO2 is similar to BaHfO3 and amounts 5.8 eV; for BaHf0.5Ti0.5O3 it decreases to 3.8 eV. We conclude that the addition of TiO2 to BaHfO3 increases significantly the dielectric permittivity but also impacts the band gap alignment. The conduction band offset shrinks, influencing the leakage current behavior.}, language = {en} } @misc{LupinaDabrowskiFormaneketal., author = {Lupina, Grzegorz and Dabrowski, Jarek Marek and Formanek, Peter and Schmeißer, Dieter and Sorge, Roland and Wenger, Christian and Zaumseil, Peter and M{\"u}ssig, Hans-Joachim}, title = {Solid-state reaction between Pr and SiO2 studied by photoelectron spectroscopy and ab initio calculations}, series = {Materials Science in Semiconductor Processing}, volume = {7}, journal = {Materials Science in Semiconductor Processing}, number = {4-6}, issn = {1369-8001}, pages = {215 -- 220}, abstract = {We report on the structural and electrical properties of Pr-based high-k dielectric films fabricated by solid-state reaction between metallic Pr and SiO2 underlayers. A non-destructive depth profiling using synchrotron radiation excited photoelectron spectroscopy (SR-PES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed to examine the chemical composition and microstructure. Ab initio calculations were done to gain insight into the physical processes involved. SR-PES results indicate that Pr deposition at room temperature (RT) leads to the formation of a Pr silicide and a Pr oxide, what is in good agreement with the scenario expected from ab initio calculations. As revealed by TEM and electrical measurements, oxidation of the reacted structures, followed by annealing, results in a stacked dielectric composed of a SiO2-based buffer with an enhanced permittivity and a Pr silicate film with a high dielectric constant. The leakage current density of 10-4 A/cm2 was measured for stacks with capacitance equivalent thickness (CET) of 1.5 nm prepared by evaporation of the Pr layer on a 1.8 nm SiO2 film, followed by oxidation in air ambient and annealing in N2 atmosphere. The capacitance-voltage (C-V) curves exhibit a large flatband voltage (VFB) shift indicating the presence of a positive charge in the stack. Switching away from the Al contacts to Au gate electrodes introduces a significant reduction of the VFB by 1.3 eV, what is much more than the change expected from the work function difference between Al and Au (not, vert, similar0.9 eV). This in turn implies that VFB is strongly affected by the gate interface electrode.}, language = {en} } @misc{MuessigDabrowskiWengeretal., author = {M{\"u}ssig, Hans-Joachim and Dabrowski, Jarek Marek and Wenger, Christian and Lupina, Grzegorz and Sorge, Roland and Formanek, Peter and Zaumseil, Peter and Schmeißer, Dieter}, title = {Ultrathin Dielectric Films Grown by Solid Phase Reaction of Pr with SiO2}, series = {MRS Proceedings}, volume = {811}, journal = {MRS Proceedings}, issn = {1946-4274}, pages = {D7.10.}, language = {en} } @incollection{SchmeisserLupinaMuessig, author = {Schmeißer, Dieter and Lupina, Grzegorz and M{\"u}ssig, Hans-Joachim}, title = {High reactivity of Pr on oxide covered 4H-SiC}, series = {Bessy annual report 2003}, booktitle = {Bessy annual report 2003}, publisher = {Bessy}, address = {Berlin}, pages = {408 -- 409}, language = {en} } @misc{LupinaSchroederDabrowskietal., author = {Lupina, Grzegorz and Schroeder, Thomas and Dabrowski, Jarek Marek and Schmeißer, Dieter and Hoffmann, Patrick}, title = {Praseodymium silicate layers with atomically abrupt interface on Si(100)}, series = {Applied Physics Letters}, volume = {87}, journal = {Applied Physics Letters}, number = {5}, issn = {0003-6951}, pages = {S. 092901}, language = {en} } @phdthesis{Lupina, author = {Lupina, Grzegorz}, title = {Praseodymium Silicate high-k dielectrics on Si(001)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-421}, language = {en} } @article{LupinaSchroederSchmeisseretal., author = {Lupina, Grzegorz and Schroeder, Thomas and Schmeißer, Dieter and Dabrowski, Jarek Marek}, title = {Praseodymium Silicate Films on Si(100) for Gate Dielectric Applications: Physical and Electrical Characterization}, language = {en} } @misc{SchroederLupinaSeifarthetal., author = {Schroeder, Thomas and Lupina, Grzegorz and Seifarth, Olaf and Tallarida, Massimo and Schmeißer, Dieter}, title = {Synchrotron radiation x-ray photoelectron spectroscopy study on the interface chemistry of high-k PrxAl2-xO3 (x=0-2) dielectrics on TiN for dynamic random access memory applications}, series = {Journal of Applied Physics}, volume = {102}, journal = {Journal of Applied Physics}, number = {1}, issn = {0021-8979}, pages = {014103}, language = {en} } @article{SohalLupinaLippertetal., author = {Sohal, Rakesh and Lupina, Grzegorz and Lippert, Gunther and Wenger, Christian and Seifarth, Olaf and Schr{\"o}der, Thomas and Tallarida, Massimo and Schmeißer, Dieter}, title = {Interface chemistry of high-k PrxAl2-xO3 (x=2-0) dielectrics on TiN for dynamic random access memory applications}, language = {en} } @inproceedings{LippertDabrowskiCostinaetal., author = {Lippert, Gunther and Dabrowski, Jarek Marek and Costina, Ioan and Lupina, Grzegorz and Ratzke, Markus and Zaumseil, Peter and M{\"u}ssig, Hans-Joachim}, title = {Morphology and Composition of Praseodymium Based High-k Materials and Their Relevance to Dielectric Properties of Thin-Films}, language = {en} } @misc{ZoellnerDabrowskiZaumseiletal., author = {Z{\"o}llner, Marvin Hartwig and Dabrowski, Jarek Marek and Zaumseil, Peter and Giussani, A. and Schubert, Markus Andreas and Lupina, Grzegorz and Wilkens, Henrik and Wollschl{\"a}ger, Joachim and B{\"a}umer, Marcus and Reichling, M. and Schr{\"o}der, Thomas}, title = {On the unusual stacking behavior of twin-free, type B oriented CeO2(111) films on hexagonal Pr2O3(0001) / Si(111) systems}, series = {Physical Review}, volume = {85}, journal = {Physical Review}, number = {3}, issn = {1098-0121}, doi = {10.1103/PhysRevB.85.035302}, pages = {035302 -- 035311}, language = {en} } @misc{BartolomeoSantandreaGiubileoetal., author = {Bartolomeo, Antonio di and Santandrea, S. and Giubileo, Filippo and Romeo, Francesco and Petrosino, Mario and Citro, R. and Barbara, P. and Lupina, Grzegorz and Schr{\"o}der, Thomas and Rubino, Alfredo}, title = {Effect of back-gate on contact resistance and on channel conductance in graphene-based field-effect transistors}, series = {Diamond and Related Materials}, volume = {38}, journal = {Diamond and Related Materials}, number = {13}, issn = {0925-9635}, pages = {19 -- 23}, language = {en} } @inproceedings{SeifarthWalczykLupinaetal., author = {Seifarth, Olaf and Walczyk, Christian and Lupina, Grzegorz and Dabrowski, Jaroslaw and Weidner, G{\"u}nter and Zaumseil, Peter and Schmeißer, Dieter and Storck, Peter and M{\"u}ssig, Hans-Joachim and Schroeder, Thomas}, title = {On the electronic and dielectric characterisation of thin cubic PrO2 layers on Silicon}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 43}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 43}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 196}, abstract = {For the integration of 100 \% Ge onto the Si platform, a buffer oxide approach has been developed recently, using rare earth oxides to tune the lattice constant between the Si and the Ge. Among these buffer oxides, PrO2 is a prospective candidate with high quality crystalline growth on Si, moderated by an interfacial Pr-silicate between. In order to specify electronic properties of thin PrO2 and its interface on Si(111), especially the width of the band gap, we performed synchrotron radiation based XPS, UPS and XAS measurements at the U49/2 PGM 2 beamline at BESSY II and correlate the results with our structural characterisation performed by TEM and XRD. In order to evaluate the dielectric properties of thin PrO2 layers on Si(111), we performed temperature-, time-, voltage-, and layer thickness-dependent leakage current measurements (J-V). Here, we identified relaxation behaviour in the leakage current, successfully addressed to defect like states inside the Pr-silicate interface layer, corroborated by frequency dependent capacitance versus voltage (C-V) measurements.}, language = {en} } @inproceedings{SeifarthWalczykLupinaetal., author = {Seifarth, Olaf and Walczyk, Christian and Lupina, Grzegorz and Zaumseil, Peter and Schmeißer, Dieter and M{\"u}ssig, Hans-Joachim and Schroeder, Thomas}, title = {The electronic band diagram of thin PrO2(111) / Pr-silicate buffers on Si(111) and its relevance to dielectric properties}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 44}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 44}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {0420-0195}, pages = {S. 136}, abstract = {Thin dielectric buffers of cubic PrO2(111) on Si(111) are ideally suited to integrate Ge onto Si by moderating the lattice mismatch between the materials. The leakage current across this dielectric buffer is strongly influenced by the electronic band diagram and defects inside the band gap. Therefore, we measured the band offsets, band gaps and defect positions by means of synchrotron radiation based photoemission spectroscopy techniques (XPS and XAS) with special emphasis on the Pr-silicate interface. In a next step we compare the spectroscopic data with information from dielectric studies, based on temperature dependent leakage current studies. We observe a close relation between dielectric properties and the electronic structure.}, language = {en} } @misc{LippertDabrowskiOberbecketal., author = {Lippert, Gunther and Dabrowski, Jarek Marek and Oberbeck, Lars and Schroeder, Uwe and Costina, Ioan and Lupina, Grzegorz and Ratzke, Markus and Zaumseil, Peter and M{\"u}ssig, Hans-Joachim}, title = {Morphology and composition of selected high-k materials and their relevance to dielectric properties of thin films}, series = {Journal of the electrochemical society}, volume = {155}, journal = {Journal of the electrochemical society}, number = {5}, issn = {1945-7111}, doi = {10.1149/1.2875741}, pages = {G97 -- G114}, language = {en} } @inproceedings{TorcheMuellerHenkeletal., author = {Torche, Mohamed and M{\"u}ller, Klaus and Henkel, Karsten and Lupina, Grzegorz and Goryako, Andrey and Wollweber, J{\"u}rgen and Schmeißer, Dieter}, title = {Investigations of 3C-SiC growth on Si (001)}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Carbide was grown on Si (001) - substrates with supply of C2H2. Investigation of the interface Si/SiC (buffer layer) is essential for optimized preparation conditions, leading to a high quality of the growing SiC crystal. In addition to the lattice mismatch of 20 per cent between Si and SiC, which causes defects like dislocations or stacking faults, the chemical homogeneity of this layer is important. XPS was used to characterize the first state of SiC crystal growth on the Si substrate. Carbonizing with C2H2 leads to surface reactions which build up the buffer layer. By using electron spectroscopy, it was possible to characterize the SiC/Si (001) buffer layer, depending on the following reaction parameters: Tsubstrate , PC2H2 , PH2 , the ratio of pressures and the reaction time. The measurements were performed in terms of the content of carbide, oxide and roughness/etching-efficiency (Profilometer) for the reaction parameters above. We found, that the most critical parameter is the temperature of the substrate (Tsubstrate).}, language = {en} } @inproceedings{LupinaSchroederDabrowskietal., author = {Lupina, Grzegorz and Schroeder, Thomas and Dabrowski, Jarek Marek and Schmeißer, Dieter and M{\"u}ssig, Hans-Joachim}, title = {Ti-doping of Pr silicate layers for high-k dielectrics applications}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Near-term downscaling of the metal-oxide-semiconductor field-effect transistors (MOSFETs) requires the replacement of the SiO2 gate oxide with a material having a higher dielectric constant. Recent studies indicate that silicate materials are the most promising candidates; among them are Pr silicates. Applying a combination of x-ray photoelectron spectroscopy (XPS), electrical measurements (C-V), and ab initio calculations, we investigated the effect of thin Ti doping on the structural and electrical properties of the gate stacks composed of a Pr silicate film and a SiO2-based interfacial buffer layer. Metallic Ti was deposited at room temperature after the formation of the Pr silicate dielectric. The resulting layered structures were annealed under ultra-high vacuum (UHV) at various temperatures between 70∘C and 880∘C. XPS indicates that the evaporated layer preserves its metallic character over the whole range of UHV annealing temperatures. Synchrotron radiation XPS at BESSY II shows that large amounts of Ti atoms incorporated into the Pr silicate remain metallic even after air exposure at room temperature. Annealing in nitrogen ambient at 300∘C leads to the oxidation of these atoms so that a mixed Pr:Ti silicate is formed. We show that the so formed dielectrics exhibit an improved equivalent oxide thickness and a reduced density of interface states.}, language = {en} } @misc{NiuCapelliniLupinaetal., author = {Niu, Gang and Capellini, Giovanni and Lupina, Grzegorz and Niermann, Tore and Salvalaglio, Marco and Marzegalli, Anna and Schubert, Markus Andreas and Zaumseil, Peter and Krause, Hans-Michael and Skibitzki, Oliver and Lehmann, Michael and Montalenti, Francesco and Xie, Ya-Hong and Schr{\"o}der, Thomas}, title = {Photodetection in hybrid single layer graphene/fully coherent Ge island nanostructures selectively grown on Si nano-tip patterns}, series = {ACS Applied Materials and Interfaces}, volume = {8}, journal = {ACS Applied Materials and Interfaces}, number = {3}, issn = {1944-8252}, pages = {2017 -- 2026}, language = {en} } @misc{DabrowskiLippertAvilaetal., author = {Dabrowski, Jarek Marek and Lippert, Gunther and Avila, J. and Baringhaus, Jens and Colambo, I. and Dedkov, Yu. S. and Herziger, Felix and Lupina, Grzegorz and Maultzsch, J. and Schaffus, T. and Schr{\"o}der, Thomas and Sowinska, Małgorzata and Tegenkamp, Christoph and Vignaud, D. and Asensio, Maria Carmen}, title = {Understanding the growth mechanism of graphene on Ge/Si(001) surfaces}, series = {Scientific Reports}, journal = {Scientific Reports}, number = {6}, issn = {2045-2322}, doi = {10.1038/srep31639}, pages = {Art. 31639}, language = {en} } @misc{BartolomeoPassacantandoNiuetal., author = {Bartolomeo, Antonio di and Passacantando, Maurizio and Niu, Gang and Schlykow, Viktoria and Lupina, Grzegorz and Giubileo, Filippo and Schr{\"o}der, Thomas}, title = {Observation of field emission from GeSn nanoparticles epitaxially grown on silicon nanotip arrays}, series = {Nanotechnology}, volume = {27}, journal = {Nanotechnology}, number = {48}, issn = {1361-6528}, pages = {485707}, language = {en} }