tesi R. Miscioscia.pdf - EleA@UniSA

Chapter 4 135
μ (cm 2 V -1 s -1 )
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
μ(W g ) = - 0.27 + 0.87 W g
After Esseni's I ch extraction
0.2 0.4 0.6 0.8 1.0 1.2 1.4
Lateral grain size (μm)
figure 19: extrapolation of a linear trend from the field-effect mobilities versus mean pentacene
grain dimensions for polymeric dielectrics-based OTFTs (black symbols). Red squares are
PFTEOS:TEOS samples mobilities.
As we can observe in figure 19, the mobility trend in samples
having polymeric dielectric is strongly dependent from channel’s
morphology but also the anomaly of PFTEOS:TEOS samples is still
evident if we remind figure 13.
By interpolating all the symbols but the red ones (the first on
the left and the last on the right in the plot), we obtained an estimation
line for transistor’s performances as the channel film morphology
changes.
The major differences introduced by Ich estimation are, instead,
evident in thermal analyses that allow now to distinguish some
important features of PFTEOS:TEOS samples in comparison with
PMMA samples.
Looking at figure 20, we see that the activation energy curves
are now more separated and denote the dependence of the thermal
activation from thickness and nature of gate dielectric in OTFTs. They
still keep the usual decreasing behavior with the gate field intensity