@misc{SchmeisserMuessigDabrowski, author = {Schmeißer, Dieter and M{\"u}ssig, Hans-Joachim and Dabrowski, Jarek Marek}, title = {Silicate Layer Formation at the Pr2O3 / Si(001) Interfaces}, series = {Applied Physics Letters}, volume = {85}, journal = {Applied Physics Letters}, number = {1}, issn = {1077-3118}, pages = {88 -- 90}, abstract = {We studied Pr2O3/Si(001) interfaces by synchrotron radiation photoelectron spectroscopy and by ab initio calculations. We show that the interface formed during molecular-beam epitaxy under the oxygen partial pressure above 1\%D710-8 mbar consists of a mixed Si-Pr oxide, such as (Pr2O3)(SiO)x(SiO2)y. Neither an interfacial SiO2 nor an interfacial silicide is formed. The silicate formation is driven by a low energy of O in a PrOSi bond and by the strain in the subsurface SiOx layer. We expect that this natural interfacial Pr silicate will facilitate the integration of the high-k dielectric Pr2O3 into future complementary metal-oxide-semiconductor technologies.}, 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} } @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} } @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{SchmeisserMuellerSeifarthetal., author = {Schmeißer, Dieter and M{\"u}ller, S. and Seifarth, Olaf and Dabrowski, Jarek Marek and M{\"u}ssig, Hans-Joachim and Schroeder, Thomas}, title = {On the band gaps and electronic structure of thin single crystalline praseodymium oxide layers on Si(111)}, series = {Journal of vacuum science \& technology / B}, volume = {27}, journal = {Journal of vacuum science \& technology / B}, number = {1}, pages = {271 -- 276}, language = {en} } @inproceedings{SeifarthWilkeWalczyketal., author = {Seifarth, Olaf and Wilke, A. and Walczyk, Christian and Dabrowski, Jarek Marek and Zaumseil, Peter and Schmeißer, Dieter and M{\"u}ssig, Hans-Joachim and Schroeder, Thomas}, title = {Band gap and electronic structure determination with XAS and UPS of thin Pr-oxide films on Si(111)}, series = {Proceedings of 15th Workshop on Dielectrics in Microelectronics, Bad Saarow, 23 - 25 June 2008, Bad Saarow (Berlin)}, booktitle = {Proceedings of 15th Workshop on Dielectrics in Microelectronics, Bad Saarow, 23 - 25 June 2008, Bad Saarow (Berlin)}, pages = {285 -- 286}, language = {en} } @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} } @inproceedings{MuessigDabrowskiSchmeisser, author = {M{\"u}ssig, Hans-Joachim and Dabrowski, Jarek Marek and Schmeißer, Dieter}, title = {Interface Characterization of the High-k Gate Dielectric Pr2O3}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, booktitle = {Verhandlungen der Deutschen Physikalischen Gesellschaft}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, abstract = {Pr2O3 is currently under consideration as a potential alternative gate dielectric candidate for sub-0.1 µm Complementary Metal Oxide Semiconductor (CMOS) technology. For all thin gate dielectrics, the interface with silicon plays a key role, and in most cases is a dominant factor in determining overall electrical properties. We studied the Pr2O3/Si(001) interface by a non-destructive depth profiling using synchrotron radiation photo-electron spectroscopy and ab initio calculations. Our results provide evidence that a chemical reactive interface exists consisting of a mixed Si-Pr oxide such as (Pr2O3)x(SiO2)1-x, typically in non-stoichiometric composition. There is no formation of neither an interfacial SiO2 nor interfacial silicide: all Si-Pr bonds are oxidized and all SiO4 units dissolve in the Pr oxide. Interfacial silicates like (Pr2O3)x(SiO2)1-x are promising high-k dielectric materials because they represent incremental modification of SiO2 films by Pr ions so that the interface characteristics can be similar to Si-SiO2 interface properties. Under ultrahigh vacuum conditions, silicide formation is observed when the silicate film is heated above 800∘C. The praseodymium silicate system observed at the interface between Si(001) and Pr2O3 offers greater flexibility towards integration of Pr2O3 into future CMOS technologies.}, language = {en} }