05 Fakultät Informatik, Elektrotechnik und Informationstechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6
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Item Open Access High‐performance MEMS shutter display with metal‐oxide thin‐film transistors and optimized MEMS element(2023) Al Nusayer, Sheikh Abdullah; Schalberger, Patrick; Baur, Holger; Kleber, Florian; Fruehauf, NorbertActive matrix prestressed microelectromechanical shutter displays enable outstanding optical properties as well as robust operating performance. The microelectromechanical systems (MEMS) shutter elements have been optimized for higher light outcoupling efficiency with lower operation voltage and higher pixel density. The MEMS elements have been co-fabricated with self-aligned metal-oxide thin-film transistors (TFTs). Several optimizations were required to integrate MEMS process without hampering the performance of both elements. The optimized display process requires only seven photolithographic masks with ensuring proper compatibility between MEMS shutter and metal-oxide TFT process.Item Open Access Ultraviolet photodetectors and readout based on a‐IGZO semiconductor technology(2023) Schellander, Yannick; Winter, Marius; Schamber, Maurice; Munkes, Fabian; Schalberger, Patrick; Kuebler, Harald; Pfau, Tilman; Fruehauf, NorbertIn this work, real-time ultraviolet photodetectors are realized through metal–semiconductor–metal (MSM) structures. Amorphous indium gallium zinc oxide (a-IGZO) is used as semiconductor material and gold as metal electrodes. The readout of an individual sensor is implemented by a transimpedance amplifier (TIA) consisting of an all-enhancement a-IGZO thin-film transistor (TFT) operational amplifier and a switched capacitor (SC) as feedback resistance. The photosensor and the transimpedance amplifier are both manufactured on glass substrates. The measured photosensor possesses a high responsivity R, a low response time tRES, and a good noise equivalent power value NEP.Item Open Access High gain operational amplifier using enhancement and depletion mode a-IGZO TFTs(2022) Schellander, Yannick; Winter, Marius; Ge, Ge; Ouyang, Yunyi; Obermüller, Simon; Schalberger, Patrick; Fruehauf, NorbertAn operational amplifier (OpAmp) consisting of twenty-two dual gate amorphous IGZO (a-IGZO) thin-film transistors (TFTs) is fabricated on a glass substrate. To achieve high voltage gains enhancement and depletion mode transistors are used. The enhancement mode TFTs work as drivers and the depletion mode TFTs act as depletion loads in the OpAmp circuit. The created OpAmp has a voltage gain (G) of 54.80 dB, a cutoff frequency (fc) of 75 Hz, a unity gain frequency (fug) of 10 kHz and a slew rate ts(up/down) of 0.15/0.30 V/µs. Transistors with different threshold voltages Uth on the same substrates are realized by using different semiconductor channel thicknesses. This is possible, as an increasing layer thickness of the semiconductor leads to a reduction of the threshold voltage Uth [1].Item Open Access Printed chip interconnects for microLED displays(2025) Waldner, Kai; Baur, Holger; Schalberger, Patrick; Fruehauf, Norbert; Fuchs, Emmanuel; Ramaswamy, Prasanna; Toomey, Vincent; Drozdek, SławomirThis paper presents a newly developed process for interconnecting microICs with microLEDs through ultra‐precise dispensing of conductive silver‐based paste. Special cleaning and surface energy modification processes have been introduced to achieve interconnects with a width of 5 μm and a minimum pitch of 20 μm. The developed technology is part of the EU funded project “Building Active matrix MicroLED displays By Additive Manufacturing” (BAMBAM), which develops unique manufacturing technologies for realizing microLED displays without TFT backplanes.Item Open Access Large‐area hydrogenated amorphous silicon Schottky photosensor arrays for display integration(2025) Dettling, Marco M.; Schalberger, Patrick; Schellander, Yannick; Fruehauf, NorbertIn this work, a system for the real‐time spatially resolved detection of visible light on a large area is realized on glass. Schottky photodiodes, consisting of hydrogenated amorphous silicon (a‐Si:H) and molybdenum-tantalum (MoTa), are employed as detectors. The detectors exhibit an internal quantum efficiency of up to 70.96% and a response time smaller than 20 μs. The noise equivalent power was measured at 2.424e‐10 W/√Hz. Process compatibility with commonly employed amorphous indium gallium zinc oxide (a‐IGZO) and a‐Si:H thin‐film transistors (TFT) is shown. The driving and real‐time readout of a photosensor array is demonstrated using a microcontroller and a current‐input ADC.