cfaed Seminar Series
cfaed Seminar Series
Dr. Kornelius Tetzner , Department of Physics and Centre for Plastic Electronics, Imperial College London, UK
Sub-second photonic curing of solution-processed metal oxide thin-film transistors via high-power xenon flash treatment
, 14:00 - 15:00
TU Dresden, Werner-Hartmann-Building, Room 205/206 , Nöthnitzer Str. 66 , 01187 Dresden
The use of solution-based fabrication processes for the realisation of (opto-)electronic devices and circuits based on metal oxide semiconductors has become an attractive alternative to conventional manufacturing technologies allowing for the reduction of manufacturing costs by large-area production. Field-effect mobilities of metal oxide transistors are already well beyond those of amorphous silicon and the performance of such devices is steadily increasing due to material and process optimisation. However, solution-deposition of state-of-the-art metal oxide semiconductors typically require high curing temperatures (>200 °C) for prolonged periods of time (>60 min) in order to reach the desired electrical properties needed for high performance transistors which makes the use of inexpensive substrates such as plastic incompatible and severely hampers the production throughput. In this presentation we will demonstrate a promising approach to overcome these issues by using high-power xenon flash lamps for the rapid photo-thermal conversion of carefully selected precursor materials to semiconducting metal oxides. For the first time, we are able to fabricate low operating voltage (≤2 V) electron transporting In2O3 and ZnO transistors on glass substrates with electron mobilities of 6 cm2/Vs and 1.7 cm2/Vs, respectively with processing times for the semiconductor annealing of less than 18 seconds by using this technology. Moreover, a significant performance improvement is achieved by the photonic annealing of In2O3/ZnO heterostructure devices with field-effect mobilities of up to 35 cm2/Vs. We will show that these level of performances are comparable to reference devices fabricated via conventional thermal annealing at 250 °C for 60 min. Besides the electrical characterisation, the influence of the high intensity flash exposure on the surface topography and elemental composition of the resulting semiconductors are investigated by atomic force microscopy and x-ray photoelectron spectroscopy. Using a numerical model we are able to analyse the temperature profile in time within the thin film stack revealing a remarkable increase of the temperature up to 1000 °C in less than 1 ms on top of the device surface within the metal oxide films during each pulse while the backside of the glass substrate is nearly unaffected. Our work demonstrates the tremendous potential of photonic processing for the rapid manufacturing of metal oxide electronics on arbitrary substrate materials.
Kornelius Tetzner studied Electrical Engineering at the Technische Universität Berlin where he received the degree of a graduated engineer (Dipl.-Ing.) in 2008 and doctor of engineering (Dr.-Ing.) in 2014, respectively. During his PhD studies he worked as a research assistant at the Technische Universität Berlin from 2009-2014 focusing on the use of semiconducting liquid-crystalline polymers for large-area fabrication of electronic devices and circuits. In 2015, he started working as a research associate at Technische Universität Dresden working on additive patterning processes of organic/inorganic materials for flexible electronics. In the same year, he was awarded with a Marie-Curie fellowship and became a research associate at Imperial College London under the supervision of Professor Thomas Anthopoulos. His current research focuses on the realisation of complementary integrated circuits combining organic and inorganic semiconductors into a hybrid approach by using solution-based deposition techniques on low-temperature substrates.