TY - GEN A1 - Fritscher, Markus A1 - Uhlmann, Max A1 - Ostrovskyy, Philip A1 - Reiser, Daniel A1 - Chen, Junchao A1 - Schubert, Andreas A1 - Schulze, Carsten A1 - Kahmen, Gerhard A1 - Fey, Dietmar A1 - Reichenbach, Marc A1 - Krstic, Milos A1 - Wenger, Christian T1 - Area-efficient digital design using RRAM-CMOS standard cells T2 - 2024 IEEE Computer Society Annual Symposium on VLSI (ISVLSI) N2 - Extending the scalability of digital integrated circuits through novel device concepts is an attractive option. Among these concepts, resistive random access memory (RRAM) devices allow fast and nonvolatile operation. However, building large memristive systems is still challenging since large analog circuits have to be designed and integrated. In this paper, we propose a novel solution - the implementation of digital standard cells by the means of RRAM devices. While this methodology is universal, with applications ranging from few-device-circuits to large macroblocks, we demonstrate it for a 2T2R-cell. The benefits of using RRAM devices are demonstrated by implementing a NAND standard cell merely consuming the area of two transistors. This cell is about 25 % smaller than the equivalent CMOS NAND in the same technology. We use these cells to implement a half adder, beating the area of the equivalent CMOS implementation using more sophisticates gates by 15 %. Lastly, we fully integrate this novel standard cell into a digital standard cell library and perform a synthesis and layout of a RISC-V CPU core. KW - RRAM Y1 - 2024 SN - 979-8-3503-5411-9 SN - 979-8-3503-5412-6 U6 - https://doi.org/10.1109/ISVLSI61997.2024.00026 SN - 2159-3477 VL - 18 SP - 81 EP - 87 PB - IEEE ER - TY - GEN A1 - Reiter, Sebastian A1 - Han, Weijia A1 - Mai, Christian A1 - Spirito, Davide A1 - Jose, Josmy A1 - Zöllner, Marvin Hartwig A1 - Fursenko, Oksana A1 - Schubert, Markus Andreas A1 - Stemmler, Ivo A1 - Wenger, Christian A1 - Fischer, Inga Anita T1 - Titanium Nitride Plasmonic Nanohole Arrays for CMOS-compatible integrated refractive index sensing: influence of layer thickness on optical properties T2 - Plasmonics Y1 - 2023 U6 - https://doi.org/10.1007/s11468-023-01810-3 SN - 1557-1963 SP - 1 EP - 13 ER - TY - GEN A1 - Morales, Carlos A1 - Mahmoodinezhad, Ali A1 - Tschammer, Rudi A1 - Kosto, Yuliia A1 - Alvarado Chavarin, Carlos A1 - Schubert, Markus Andreas A1 - Wenger, Christian A1 - Henkel, Karsten A1 - Flege, Jan Ingo T1 - Combination of Multiple Operando and In-Situ Characterization Techniques in a Single Cluster System for Atomic Layer Deposition: Unraveling the Early Stages of Growth of Ultrathin Al2O3 Films on Metallic Ti Substrates T2 - Inorganics N2 - This work presents a new ultra-high vacuum cluster tool to perform systematic studies of the early growth stages of atomic layer deposited (ALD) ultrathin films following a surface science approach. By combining operando (spectroscopic ellipsometry and quadrupole mass spectrometry) and in situ (X-ray photoelectron spectroscopy) characterization techniques, the cluster allows us to follow the evolution of substrate, film, and reaction intermediates as a function of the total number of ALD cycles, as well as perform a constant diagnosis and evaluation of the ALD process, detecting possible malfunctions that could affect the growth, reproducibility, and conclusions derived from data analysis. The homemade ALD reactor allows the use of multiple precursors and oxidants and its operation under pump and flow-type modes. To illustrate our experimental approach, we revisit the well-known thermal ALD growth of Al2O3 using trimethylaluminum and water. We deeply discuss the role of the metallic Ti thin film substrate at room temperature and 200 °C, highlighting the differences between the heterodeposition (<10 cycles) and the homodeposition (>10 cycles) growth regimes at both conditions. This surface science approach will benefit our understanding of the ALD process, paving the way toward more efficient and controllable manufacturing processes. KW - Atomic layer deposition (ALD) KW - in-situ KW - operando KW - X-ray photoelectron spectroscopy KW - ellipsometry KW - quadrupol mass spectrometry (QMS) Y1 - 2023 U6 - https://doi.org/10.3390/inorganics11120477 SN - 2304-6740 VL - 11 IS - 12 ER - TY - GEN A1 - Franck, Max A1 - Dabrowski, Jarek A1 - Schubert, Markus Andreas A1 - Vignaud, Dominique A1 - Achehboune, Mohamed A1 - Colomer, Jean‐François A1 - Henrard, Luc A1 - Wenger, Christian A1 - Lukosius, Mindaugas T1 - Investigating Impacts of Local Pressure and Temperature on CVD Growth of Hexagonal Boron Nitride on Ge(001)/Si T2 - Advanced Materials Interfaces N2 - AbstractThe chemical vapor deposition (CVD) growth of hexagonal boron nitride (hBN) on Ge substrates is a promising pathway to high‐quality hBN thin films without metal contaminations for microelectronic applications, but the effect of CVD process parameters on the hBN properties is not well understood yet. The influence of local changes in pressure and temperature due to different reactor configurations on the structure and quality of hBN films grown on Ge(001)/Si is studied. Injection of the borazine precursor close to the sample surface results in an inhomogeneous film thickness, attributed to an inhomogeneous pressure distribution at the surface, as shown by computational fluid dynamics simulations. The additional formation of nanocrystalline islands is attributed to unfavorable gas phase reactions due to the radiative heating of the injector. Both issues are mitigated by increasing the injector‐sample distance, leading to an 86% reduction in pressure variability on the sample surface and a 200 °C reduction in precursor temperature. The resulting hBN films exhibit no nanocrystalline islands, improved thickness homogeneity, and high crystalline quality (Raman FWHM = 23 cm−1). This is competitive with hBN films grown on other non‐metal substrates but achieved at lower temperature and with a low thickness of only a few nanometers. KW - Boron Nitride KW - 2D material Y1 - 2025 U6 - https://doi.org/10.1002/admi.202400467 SN - 2196-7350 VL - 12 IS - 1 PB - Wiley ER - TY - GEN A1 - Morales, Carlos A1 - Gertig, Max A1 - Kot, Małgorzata A1 - Alvarado, Carlos A1 - Schubert, Markus Andreas A1 - Zoellner, Marvin Hartwig A1 - Wenger, Christian A1 - Henkel, Karsten A1 - Flege, Jan Ingo T1 - In situ X‐ray photoelectron spectroscopy study of atomic layer deposited cerium oxide on SiO₂ : substrate influence on the reaction mechanism during the early stages of growth T2 - Advanced materials interfaces N2 - Thermal atomic layer deposition (ALD) of cerium oxide using commercial Ce(thd)4 precursor and O3 on SiO2 substrates is studied employing in‐situ X‐ray photoelectron spectroscopy (XPS). The system presents a complex growth behavior determined by the change in the reaction mechanism when the precursor interacts with the substrate or the cerium oxide surface. During the first growth stage, non‐ALD side reactions promoted by the substrate affect the growth per cycle, the amount of carbon residue on the surface, and the oxidation degree of cerium oxide. On the contrary, the second growth stage is characterized by a constant growth per cycle in good agreement with the literature, low carbon residues, and almost fully oxidized cerium oxide films. This distinction between two growth regimes is not unique to the CeOx/SiO2 system but can be generalized to other metal oxide substrates. Furthermore, the film growth deviates from the ideal layer‐by‐layer mode, forming micrometric inhomogeneous and defective flakes that eventually coalesce for deposit thicknesses above 10 nm. The ALD‐cerium oxide films present less order and a higher density of defects than films grown by physical vapor deposition techniques, likely affecting their reactivity in oxidizing and reducing conditions. KW - Atomic Layer Deposition (ALD) KW - Cerium oxide KW - In-situ X-ray Photoelectron spectroscopy (in-situ XPS) KW - Growth model KW - Substrate influence Y1 - 2025 U6 - https://doi.org/10.1002/admi.202400537 SN - 2196-7350 VL - 12 IS - 5 SP - 1 EP - 13 PB - Wiley CY - Weinheim ER -