Project leader: Dr. D.N. Kouvatsos
Post Doctoral Scientists: D.C. Moschou
External collaborators: C.A. Dimitriadis (University of Thessaloniki), G.J. Papaioannou (University of Athens), N. Stojadinovic (University of Nis), A.T. Voutsas (Sharp Laboratories of America)
The project general research objective is the development and characterization of new technologies for thin film transistors and other thin film based devices. The principal particular objective for the past decade has been the optimization of the active layer of polysilicon films obtained using advanced excimer laser crystallization methods and of the resulting performance parameters of thin film transistors (TFTs) fabricated in such films. Such advanced TFTs are necessary for next generation large area electronics systems. Specifically, the targets of the TFT and poly-Si thin film investigation are:
- Evaluation of device parameter hot carrier and irradiation stress-induced degradation and identification of ageing mechanisms in TFTs fabricated in advanced excimer laser annealed (ELA) polysilicon films with sequential lateral solidification (SLS).
- Investigation of the influence of the crystallization technique and the film thickness on TFT performance, defect densities and degradation for technology optimization.
- Investigation of effects of variations in the transistor structure and in the fabrication process on device performance and reliability.
- Investigation of polysilicon active layer defects using transient drain current and noise analysis in ELA TFTs.
- Assessment of material properties of poly-Si thin films using optical measurements.
On the application level, the project aims at the utilization of these advanced TFTs in the development of novel TFT-addressed displays and microsystems, in collaboration with various research and development partners. Such systems would incorporate thin film sensors and other elements, or possibly thin film polysilicon photovoltaics. Polysilicon film characterization would determine the efficiency of silicon photovoltaic elements as a function of the grain size and geometry. Another possibility being pursued is support for the development of thin film photoelectric sensor – ZnO TFT microsystem modules. Detailed proposals on these subjects with European consortia have been formulated.