SBMicro Invited Talk: Tayeb Mohammed-Brahim

Tayeb Mohammed-Brahim
Rennes 1 University – France
Friday, Aug. 31 – 13:40h – Malbec A

SBMICRO INVITED TALK:
Organic Thin Film Transistors: Experimental and Modeling

Flexible electronics becomes a major research domain due to the fast growing market. The overall revenue of wearable technology was $38 billion in 2017 and it is expected to grow over $85 billion in 2022. This electronics is more and more mainly based on organic films with disordered structure, amorphous or polycrystalline with very small crystalline grains. The talk will show a direct link between the polycrystalline structure and the electrical performance of the thin film transistors made on these films. The field effect mobility is proportional to the grain size and the surface roughness affect the subthreshold slope. The usual Seto model and its derivatives established for polysilicon films and thin film transistors based on are applicable for organic based transistors.

The second point of the talk will focus on the modeling of the transfer and output characteristics of the organic transistors. Usual model of the drain current of MOSFETs is shown to be applicable to organic transistors with some changes taking account the disordered structure of organic films. With this change, the experimental characteristics of the organic transistor are very well fitted.

The final part of the talk will focus on the dynamic answer on the organic transistors. The frequency limit is usually limited by the overlap capacitances, the length of the active channel, the transconductance or the mobility. For organic transistors, the time to create the channel under sudden application of the gate voltage is showed to play an important role in the frequency limitation.

Speaker’s Biography:

Tayeb Mohammed-Brahim is currently an emeritus professor in Rennes 1 University (France). He was previously Head of Microelectronics & Microsensors Department of the Institute of Electronics and Telecommunications of Rennes and Director of the Common Center on Microelectronics in the west of France. He got his Ph.D. (Doctorat d’Etat) in Paris-XI University (France) and he founded the thin-film Laboratory in Algiers University (Algeria). Then he moved to Caen University (France) where he created the reliability Laboratory. After that and since 2000, he moved to Rennes 1 University where he became on 2007 the head of Microelectronics Group becoming the Microelectronics and Microsensors Department after 2012. He is mainly involved in the field of thin film and nanowire devices based on amorphous, micro-poly crystalline silicon films or organic films: Photovoltaic cells, Thin Film Transistors for flat panel displays and OLEDs, chemical and mechanical sensors. Presently, his main activities focus on flexible electronics, particularly on flexible organic electronics. He is the author of more than 300 papers on these different fields.