Gate-planarized organic polymer thin film transistors

Abstract

We report in this paper the fabrication and characterization of a new gate-planarized organic polymer thin-film transistor (GP OP-TFT). We describe in detail the effects of the measurement procedure on the GP OP-TFT electrical characteristics and extracted parameters and show that it is extremely critical to carefully control the electrical measurement conditions to obtain accurate and meaningful results, before any material optimization is undertaken. We also describe the importance of normalization of electrical characteristics and extracted parameters for a proper comparison of different devices. Finally, we report and analyze the gate voltage and channel length dependence of the TFT field-effect mobility.

Influence of gate dielectrics on electrical properties of F8T2 polyfluorene thin film transistors

“…The F8T2 was spun directly onto a cleaned, native dielectric. These µ FE values are consistent with those reported recently by groups using F8T2 in which monolayer treatments on the gate dielectric surface were not performed 16,20 . …”

“…To compare the performance of devices using gate dielectrics with different dielectric constants, normalization of the transfer characteristics to charge 16 is needed. The electrical charge (Q i ) induced by the gate insulator at he F8T2-gate insulator interface (in C/cm 2 ) is given by Q i = C i * V gs .…”

Organic‐polymer thin‐film transistors for active‐matrix flat‐panel displays?

“…1. 7 The devices use benzocyclobutene (BCB) as the gate-planarization material, amorphous-silicon nitride deposited by plasmaenhanced chemical vapor deposition (PECVD) as the gate insulator, and ITO as source and drain electrodes. Our typical TFT channel width and length are 50-100 and 6-100 µm, respectively.…”

“…For the transfer characteristics, the source is grounded, the drain voltage is held constant, and the gate voltage is swept from negative to positive. 7 Typical OP-TFT transfer (drain current versus source-drain voltage) and output (drain current versus source-gate voltage) characteristics are plotted in Figs. 2(a) and 2(b), respectively.…”

“…This deviation from the ideal MOSFET behavior is commonly observed in a-Si:H 15 and organic TFTs. 7,16 It has often been associated with the dispersive transport of carriers in the amorphous semiconductor. 15,17 More precisely, the fundamental TFT equations for the linear regime can be modified to include an additional parameter, γ, representative of the transfer characteristic non-linearity at low V DS , as follows: (6) In the saturation regime, the TFT equation becomes (7) where µ 0 lin and µ 0 sat are fitting parameters associated with the field-effect mobility.…”