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HL: Halbleiterphysik

HL 50: Poster II

HL 50.43: Poster

Donnerstag, 30. März 2006, 16:30–19:00, P3

Scaling behaviour of sub-µm OFETs with different active-layer materials — •O. Rost, M. Leufgen, G. Schmidt, J. Geurts, and L. W. Molenkamp — Physikalisches Institut der Universität Würzburg, Am Hubland, 97074 Würzburg

The downscaling behaviour of OFETs is influenced by the crystallinity of the organic semiconductor. Therefore, we analysed different organic semiconductors with different coating methods using templates of 20 nm thin SiO₂ dielectric with metal source/drain bottom contacts. The channel length L was varied from 5µm to 100 nm. UHV deposited dihexylquaterthiophene (DH4T) resulted in a polycrystalline thin film. The mobility was beyond 0.01cm²/Vs. A spin coated poly-triarylamine based semiconductor (amorphous) had mobility values up to 0.01cm²/Vs. Dithiophene-tetrathiafulvalene (DT-TTF) was drop cast from solution resulting in large single crystals. Here, mobility values up to 1 cm²/Vs were achieved. The presentation compares the scaling behaviour of the characteristic FET-parameters: mobility, threshold voltage and on/off-ratio. It also reports on the aspect of oncoming short channel effects, which in our case took place at about L = 200 nm, regardless of the material.