TY - JOUR A1 - Steglich, Patrick A1 - Mai, Christian A1 - Villringer, Claus A1 - Dietzel, Birgit A1 - Bondarenko, Siegfried A1 - Ksianzou, Viachaslau A1 - Villasmunta, Francesco A1 - Zesch, Christoph A1 - Pulwer, Silvio A1 - Burger, Martin A1 - Bauer, Joachim A1 - Heinrich, Friedhelm A1 - Schrader, Sigurd A1 - Vitale, Francesco A1 - De Matteis, Fabio A1 - Prosposito, Paolo A1 - Casalboni, Mauro A1 - Mai, Andreas T1 - Silicon-organic hybrid photonics: an overview of recent advances, electro-optical effects and CMOS integration concepts JF - Journal of Physics: Photonics N2 - In recent decades, much research effort has been invested in the development of photonic integrated circuits, and silicon-on-insulator technology has been established as a reliable platform for highly scalable silicon-based electro-optical modulators. However, the performance of such devices is restricted by the inherent material properties of silicon. An approach to overcoming these deficiencies is to integrate organic materials with exceptionally high optical nonlinearities into a silicon-on-insulator photonic platform. Silicon–organic hybrid photonics has been shown to overcome the drawbacks of silicon-based modulators in terms of operating speed, bandwidth, and energy consumption. This work reviews recent advances in silicon–organic hybrid photonics and covers the latest improvements to single components and device concepts. Special emphasis is given to the in-device performance of novel electro-optical polymers and the use of different electro-optical effects, such as the linear and quadratic electro-optical effect, as well as the electric-field-induced linear electro-optical effect. Finally, the inherent challenges of implementing non-linear optical polymers on a silicon photonic platform are discussed and a perspective for future directions is given. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13882 SN - 2515-7647 VL - 3 IS - 2 ER - TY - CHAP A1 - Villasmunta, Francesco A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Schrader, Sigurd A1 - Schenk, Harald A1 - Mai, Andreas A1 - Regehly, Martin ED - Chen, Ray T. ED - Schröder, Henning T1 - Design, fabrication, and characterization of integrated optical through-silicon waveguides for 3D photonic interconnections T2 - Optical Interconnects XXIV N2 - In the context of an ever-growing volume of data generated by established and emerging technologies, such as 5G, the Internet of Things, artificial intelligence, machine learning, blockchain, and virtual reality, faster communication speed is demanded by data centers and high-performance computing. Transceiver requirements surged from 100 to 400 Gb/s and beyond. In this scenario, photonics aims to enable Tb/s optical communication at energies below 1 pJ/bit. Targeting higher communication rates while maintaining a low power budget can significantly benefit from 3D photonic chip architectures. This paper presents the simulation-based design, fabrication, and characterization of a monolithically integrated optical through-silicon waveguide that facilitates the connection between different surfaces of a silicon chip. Deep reactive ion etching was employed in both the Bosch and Cryogenic variants to evaluate the effect of sidewall roughness on propagation losses. The mechanical stability of the waveguide was ensured by interrupting the annular trench with a bridging structure. The high-refractive-index contrast to air provides tight light confinement for a core size of up to 50 μm and multimode operation at 1550 nm. The morphology was characterized using scanning electron microscopy (SEM), and optical transmission characterization was performed using relative power loss measurements. A tunable laser source was buttcoupled to a waveguide to analyze light transmission efficiency. Preliminary measurements using single-mode fiber show that the transmitted values exceeded 99% for all structures. KW - multimode photonics KW - cryogenic etching KW - ICP-DRIE KW - optical interconnects KW - silicon photonics KW - 3D chip stacking Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-19759 VL - 12892 PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - JOUR A1 - Bauer, Joachim A1 - Fursenko, Oksana A1 - Marschmeyer, Steffen A1 - Heinrich, Friedhelm A1 - Villasmunta, Francesco A1 - Villringer, Claus A1 - Zesch, Christoph A1 - Schrader, Sigurd T1 - Spectroscopic reflectometry for characterization of Through Silicon Via profile of Bosch etching process JF - Journal of Vacuum Science & Technology B N2 - Through Silicon Via (TSV) technology is a key in 3D integration of circuits by the creation of interconnects using vias, which go through the full silicon wafer. Typically, a highly-selective Bosch Si etch process is used. It is characterized by a high etch rate at a high aspect ratio, whereby scallops on the sidewalls are generated. In this work, square via arrays with dimensions from 3 to 50 μm and up to 300 μm depth were fabricated and analyzed by spectroscopic reflectometry. The reflectometric data are compared to simulations by a novel theoretical approach. In order to simulate the reflectance spectra of TSV arrays, a combination of 2D and 3D rigorous coupled wave analysis was applied. Besides the via depth, the sidewall angle and the corner radius of the bottom profile were considered in the model. The general requirements on spectral resolution in TSV metrology are discussed. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-16093 VL - 37 IS - 6 PB - American Vacuum Society (AVS) ER - TY - JOUR A1 - Bauer, Joachim A1 - Heinrich, Friedhelm A1 - Villasmunta, Francesco A1 - Villringer, Claus A1 - Reck, Johanna A1 - Peters, Sven A1 - Treffer, Alexander A1 - Kuhnt, Christian A1 - Marschmeyer, Steffen A1 - Fursenko, Oksana A1 - Stolarek, David A1 - Mai, Andreas A1 - Regehly, Martin T1 - Reflectometric method for measuring residual oxides in through-silicon vias for 3D chip integration JF - Optics Express N2 - A significant aspect of fabricating 3D chip architectures is ensuring proper contact between the different layers of the chip, which often requires removing the underside of isolation layers before filling vias with conductive material. Currently, scanning electron microscopy is the established method for investigating such structures. In this paper, we propose a rapid, non-destructive optical analysis technique for the simultaneous measurement of through-silicon vias (TSV) depths, silicon wafer thickness, and residual oxide thickness. The proposed method utilizes Fourier peak shift analysis (FPSA) of reflectance measurements in the near-infrared (1200 nm—2200 nm) spectral regions. The application of FPSA to representative samples taken from a commercial TSV integration process for MEMS and CMOS fabrication demonstrated good agreement with reference scanning electron microscopy measurements, confirming the feasibility of the method for in-line and in-situ metrology. The results indicate that FPSA has great potential for real-time process monitoring and control during 3D chip manufacturing. KW - effective refractive index KW - Fourier transforms KW - near infrared KW - ray tracing KW - scanning electron microscopy KW - thin film Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20633 VL - 33 IS - 15 SP - 32175 EP - 32189 PB - Optica ER - TY - CHAP A1 - Pulwer, Silvio A1 - Fiebelkorn, Richard A1 - Zesch, Christoph A1 - Steglich, Patrick A1 - Villringer, Claus A1 - Villasmunta, Francesco A1 - Gedat, Egbert A1 - Handrich, Jan A1 - Schrader, Sigurd A1 - Vandenhouten, Ralf T1 - Endoscopic orientation by multimodal data fusion T2 - Proc. SPIE 10931, MOEMS and Miniaturized Systems XVIII N2 - To improve the feasibility of endoscopic inspection processes we developed a system that provides online information about position, orientation and viewing direction of endoscopes, to support the analysis of endoscopic images and to ease the operational handling of the equipment. The setup is based on an industrial endoscope consisting of a camera, various MEMS and multimodal data fusion. The software contains algorithms for feature and geometric structure recognition as well as Kalman filters. To track the distal end of the endoscope and to generate 3D point cloud data in real time the optical and photometrical characteristics of the system are registered and the movement of the endoscope is reconstructed by using image processing techniques. KW - endoscope KW - orientation KW - Kalman filter KW - visual odometry KW - mems KW - gyroscope KW - accelerometer Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-11420 SN - 1996-756X ER - TY - JOUR A1 - Villasmunta, Francesco A1 - Heise, Patrick A1 - Breiter, Manuela A1 - Schrader, Sigurd A1 - Schenk, Harald A1 - Regehly, Martin A1 - Mai, Andreas T1 - Monolithically Integrated Optical Through-Silicon Waveguides for 3D Chip-to-Chip Photonic Interconnects JF - IEEE Journal of Selected Topics in Quantum Electronics N2 - The scaling limitations of electrical interconnects are driving the demand for efficient optical chip-to-chip links. We report the first monolithic integration of air-clad optical through-silicon waveguides in silicon, fabricated via Bosch and cryogenic deep reactive-ion etching. Rib, single-bridge, and double-bridge designs with 50 μm cores and up to 150 μm propagation lengths have been evaluated. Cryogenic-etched rib waveguides achieve the highest median transmission (66%, −1.80 dB), compared to Bosch-etched ribs (62%, −2.08 dB). Across all geometries, 3 dB alignment windows range from 9.3 μm to 49.2 μm, with Bosch-etched double-bridge waveguides providing the broadest tolerance. We show that geometric fidelity outweighs sidewall roughness for transmission and alignment in these large-core, multimode optical through-silicon waveguides. This technology provides a scalable, complementary metal-oxide semiconductor-compatible pathway toward 3D photonic interconnects. KW - optical waveguide KW - optical device fabrication KW - silicon KW - three-dimensional display KW - optical loss KW - optical interconnection KW - coupling KW - optical surface wave KW - optical coupling KW - coupler KW - silicon photonics KW - three-dimensional integrated circuit KW - through-silicon vias (TSV) Y1 - 2026 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20828 VL - 32 IS - 2 PB - IEEE ER -