TY - GEN A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek A1 - Hinrich, S. T1 - Formation of atomically smooth, ultrathin oxides on Si(113) T2 - Solid state electronics Y1 - 2001 SN - 0038-1101 VL - 45 IS - 8 SP - 1219 EP - 1231 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - The Pr2O3 / Si (001) interface studied by synchrotron radiation photo-electron spectroscopy T2 - Solid State Electronics N2 - Pr2O3 is currently under consideration as a potential replacement for SiO2 as the gate-dielectric material for sub-0.1micro m complementary metal-oxide-semiconductor (CMOS) technology. We studied the Pr2O3/Si(0 0 1) interface by a non-destructive depth profiling using synchrotron radiation photoelectron spectroscopy. Our data suggests that there is no silicide formation at the interface. Based on reported results, a chemical reactive interface exists, consisting of a mixed Si-Pr oxide such as (Pr2O3)x(SiO2)1?x, i.e. as a silicate phase with variable silicon content. This pseudo-binary alloy at the interface offers large flexibility toward successful integration of Pr2O3 into future CMOS technologies. KW - High-k dielectric material KW - Pr2O3 KW - Interface KW - Silicate Y1 - 2003 SN - 0038-1101 VL - 47 IS - 10 SP - 1607 EP - 1611 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Stability and electronic properties of silicates in the system SiO2 - Pr2O3 - Si(001) T2 - Journal of Physics: Condensed Matter N2 - Pr2O3 is one of the most promising hetero-oxides that are the candidates of choice to replace SiO2 as the gate dielectric material for sub-0.1 micrometer CMOS technology. In order to enable process integration, however, hetero-oxides require substantial characterization. In particular, the basic interaction mechanisms at the interface to the silicon substrate are the key issues. A solid knowledge of these mechanisms is required to address reliability arguments. The challenges in material science are to understand the chemical bonding of the hetero-oxides and Si on a microscopic scale. We report on the specific variations in the electronic structure which are evident in the valence band features around resonant excitation at the Pr 4d threshold. We also determine the valance band discontinuities at the Pr2O3/Si(001) interface and follow the changes in the surface potentials to develop a band scheme, a prerequisite to understanding the properties of charge transport across that interface. Y1 - 2004 SN - 1361-648X VL - 16 IS - 2 SP - 153 EP - 160 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek T1 - Silicate Layer Formation at the Pr2O3 / Si(001) Interfaces T2 - Applied Physics Letters N2 - 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. Y1 - 2004 SN - 1077-3118 VL - 85 IS - 1 SP - 88 EP - 90 ER - TY - GEN A1 - Lupina, Grzegorz A1 - Dabrowski, Jarek Marek A1 - Formanek, Peter A1 - Schmeißer, Dieter A1 - Sorge, Roland A1 - Wenger, Christian A1 - Zaumseil, Peter A1 - Müssig, Hans-Joachim T1 - Solid-state reaction between Pr and SiO2 studied by photoelectron spectroscopy and ab initio calculations T2 - Materials Science in Semiconductor Processing N2 - 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. KW - High-k dielectrics KW - Photoelectron spectroscopy KW - Interface reaction Y1 - 2004 SN - 1369-8001 VL - 7 IS - 4-6 SP - 215 EP - 220 ER - TY - GEN A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek A1 - Wenger, Christian A1 - Lupina, Grzegorz A1 - Sorge, Roland A1 - Formanek, Peter A1 - Zaumseil, Peter A1 - Schmeißer, Dieter T1 - Ultrathin Dielectric Films Grown by Solid Phase Reaction of Pr with SiO2 T2 - MRS Proceedings Y1 - 2004 SN - 1946-4274 VL - 811 ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Pr4f occupancy and VB/CB band offsets of Pr2O3 at the interface to Si(001) and SiC(0001) surfaces T2 - MRS Proceedings Y1 - 2004 SN - 1946-4274 VL - 811 ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Lupina, Grzegorz A1 - Müssig, Hans-Joachim T1 - High reactivity of Pr on oxide covered 4H-SiC T2 - Bessy annual report 2003 Y1 - 2004 SP - 408 EP - 409 PB - Bessy CY - Berlin ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Pr-silicate formation on SiO2 covered 3C-SiC(111) T2 - Physics of semiconductors, 27th International Conference on the Physics of Semiconductors Y1 - 2005 SN - 0-7354-0257-4 SP - 75 EP - 76 PB - AIP, American Inst. of Physics CY - New York, NY ER - TY - GEN A1 - Schmeißer, Dieter A1 - Müller, S. A1 - Seifarth, Olaf A1 - Dabrowski, Jarek Marek A1 - Müssig, Hans-Joachim A1 - Schroeder, Thomas T1 - On the band gaps and electronic structure of thin single crystalline praseodymium oxide layers on Si(111) T2 - Journal of vacuum science & technology / B KW - band gabs KW - electronic structure KW - oxide layers Y1 - 2009 VL - 27 IS - 1 SP - 271 EP - 276 ER - TY - CHAP A1 - Seifarth, Olaf A1 - Wilke, A. A1 - Walczyk, Christian A1 - Dabrowski, Jarek Marek A1 - Zaumseil, Peter A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim A1 - Schroeder, Thomas T1 - Band gap and electronic structure determination with XAS and UPS of thin Pr-oxide films on Si(111) T2 - Proceedings of 15th Workshop on Dielectrics in Microelectronics, Bad Saarow, 23 - 25 June 2008, Bad Saarow (Berlin) KW - band gab KW - XAS KW - UPS KW - Si(111) Y1 - 2008 SP - 285 EP - 286 ER - TY - CHAP A1 - Lippert, Gunther A1 - Dabrowski, Jarek Marek A1 - Costina, Ioan A1 - Lupina, Grzegorz A1 - Ratzke, Markus A1 - Zaumseil, Peter A1 - Müssig, Hans-Joachim T1 - Morphology and Composition of Praseodymium Based High-k Materials and Their Relevance to Dielectric Properties of Thin-Films Y1 - 2007 ER - TY - GEN A1 - Dudek, Piotr T. A1 - Lupina, Grzegorz A1 - Kozłowski, Grzegorz A1 - Zaumseil, Peter A1 - Bauer, Jakob A1 - Fursenko, Oksana A1 - Dabrowski, Jarek Marek A1 - Schmidt, R. A1 - Lippert, Gunther A1 - Müssig, Hans-Joachim A1 - Schröder, Thomas A1 - Schmeißer, Dieter A1 - Zschech, Ehrenfried T1 - Atomic-scale engineering of future high-k dynamic random access memory dielectrics: The example of partial Hf substitution by Ti in BaHfO3 T2 - Journal of Vacuum Science and Technology / B Y1 - 2011 SN - 2166-2754 VL - 29 IS - 1 ER - TY - CHAP A1 - Seifarth, Olaf A1 - Walczyk, Christian A1 - Lupina, Grzegorz A1 - Dabrowski, Jaroslaw A1 - Weidner, Günter A1 - Zaumseil, Peter A1 - Schmeißer, Dieter A1 - Storck, Peter A1 - Müssig, Hans-Joachim A1 - Schroeder, Thomas T1 - On the electronic and dielectric characterisation of thin cubic PrO2 layers on Silicon T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 43 N2 - 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. Y1 - 2008 UR - http://www.dpg-verhandlungen.de/year/2008/conference/berlin/part/df/session/12/contribution/6 SN - 0420-0195 SP - S. 196 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Seifarth, Olaf A1 - Walczyk, Christian A1 - Lupina, Grzegorz A1 - Zaumseil, Peter A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim A1 - Schroeder, Thomas T1 - The electronic band diagram of thin PrO2(111) / Pr-silicate buffers on Si(111) and its relevance to dielectric properties T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 44 N2 - 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. Y1 - 2009 UR - http://www.dpg-verhandlungen.de/year/2009/conference/dresden/part/df/session/6/contribution/5 SN - 0420-0195 SP - S. 136 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Dudek, Peter A1 - Lupina, Grzegorz A1 - Kozłowski, Grzegorz A1 - Dabrowski, Jarek Marek A1 - Lippert, Gunther A1 - Müssig, Hans-Joachim A1 - Schmeißer, Dieter A1 - Schroeder, Thomas T1 - Band structure and electrical properties of MBE grown HfO2 - based alkaline earth perovskites T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft, Reihe 6, Bd. 45 N2 - 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. Y1 - 2010 UR - http://www.dpg-verhandlungen.de/year/2010/conference/regensburg/part/ds/session/24/contribution/4 SN - 0420-0195 SP - S. 232 PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - GEN A1 - Lippert, Gunther A1 - Dabrowski, Jarek Marek A1 - Oberbeck, Lars A1 - Schroeder, Uwe A1 - Costina, Ioan A1 - Lupina, Grzegorz A1 - Ratzke, Markus A1 - Zaumseil, Peter A1 - Müssig, Hans-Joachim T1 - Morphology and composition of selected high-k materials and their relevance to dielectric properties of thin films T2 - Journal of the electrochemical society Y1 - 2008 U6 - https://doi.org/10.1149/1.2875741 SN - 1945-7111 VL - 155 IS - 5 SP - G97 EP - G114 ER - TY - CHAP A1 - Müssig, Hans-Joachim A1 - Dabrowski, Jarek Marek A1 - Schmeißer, Dieter T1 - Interface Characterization of the High-k Gate Dielectric Pr2O3 T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - 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. KW - high-k KW - Pr2O3 KW - X-ray photoelectron spectroscopy (XPS) KW - ab inito calculations KW - depth profiling KW - silicate Y1 - 2003 UR - http://www.dpg-verhandlungen.de/year/2003/conference/dresden/part/hl/session/40/contribution/1?lang=de PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Stability and electronic properties of silicates in the system SiO2 - Pr2O3 - Si(001) T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - Hetero- oxides are the candidates to replace SiO2 as the gate dielectric material for sub-0.1µm CMOS technology. In particular, the basic interaction mechanisms at the interface are a key issue and a solid knowledge of these mechanisms is required to address reliability issues. The challenge in material science is to understand the chemical bonding of the hetero oxides and Si on a microscopic scale. This report focuses on the interaction of the high dielectric constant (DK) material Pr2O3 with SiO2 and the bare Si(001) surface. Photoelectron spectroscopy (PES) using tunable Synchrotron radiation (undulator U49/2 at BESSY II) is shown to provide spectroscopic information which is used for characterization of the electronic structure elements at the interface as well as for a non-destructive depth profiling. The chemical state of the Si atoms at the interface is identified and the chemical stability of the various oxide phases is discussed. We determine the variation of the elemental composition across the interface and follow the stability of the silicate phase. KW - Pr2O3 KW - high-k KW - X-ray photoelectron spectroscopy (XPS) KW - silicate Y1 - 2004 UR - http://www.dpg-verhandlungen.de/year/2004/conference/regensburg/part/hl/session/31/contribution/3?lang=de PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER - TY - CHAP A1 - Lupina, Grzegorz A1 - Schroeder, Thomas A1 - Dabrowski, Jarek Marek A1 - Schmeißer, Dieter A1 - Müssig, Hans-Joachim T1 - Ti-doping of Pr silicate layers for high-k dielectrics applications T2 - Verhandlungen der Deutschen Physikalischen Gesellschaft N2 - 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. KW - high-k KW - X-ray photoelectron spectroscopy KW - ab inito calculations KW - Capacitance-voltage measurements KW - Pr silicate Y1 - 2005 UR - http://www.dpg-verhandlungen.de/year/2005/conference/berlin/part/df/session/6/contribution/5?lan=en PB - Deutsche Physikalische Gesellschaft CY - Bad Honnef ER -