An experimental study of contact effects in organic thin film transistors

We report on parasitic contact effects in organic thin film transistors (OTFTs) fabricated with pentacene films. The influence on the OTFT performance of the source and drain contact metal and the device design was investigated. Top contact (TC) and bottom contact (BC) gated transmission line model (gated-TLM) test structures were used to extract the combined parasitic contact resistance as a function of gate voltage swing and drain-source voltage for OTFTs with gold source and drain contacts. For comparison BC test structures with palladium contacts were studied. Differences in the bias dependence of the contact resistance for TC and BC OTFTs indicate that charge injection and device performance are strongly affected by the device design and processing. The results from this investigation show that TC and BC device performances may be contact limited for high mobility OTFTs with channel lengths less than 10μm.

[1]  Robert A. Street,et al.  Contact effects in polymer transistors , 2002 .

[2]  Thomas N. Jackson,et al.  Pentacene-based organic thin-film transistors , 1997 .

[3]  Norbert Koch,et al.  Conjugated organic molecules on metal versus polymer electrodes: Demonstration of a key energy level alignment mechanism , 2003 .

[4]  T. Jackson,et al.  Contact Dependence of α-Sexithienyl Thin Film Transistor Characteristics , 1995 .

[5]  George G. Malliaras,et al.  Charge injection and recombination at the metal–organic interface , 1999 .

[6]  Neil J. Watkins,et al.  Electronic structure symmetry of interfaces between pentacene and metals , 2002 .

[7]  John A. Rogers,et al.  Contact resistance in organic transistors that use source and drain electrodes formed by soft contact lamination , 2003 .

[8]  Vladimir Arkhipov,et al.  Charge injection into light-emitting diodes: Theory and experiment , 1998 .

[9]  Ian G. Hill,et al.  Numerical simulations of contact resistance in organic thin-film transistors , 2005 .

[10]  T. Jackson,et al.  Stacked pentacene layer organic thin-film transistors with improved characteristics , 1997, IEEE Electron Device Letters.

[11]  T. Jackson,et al.  Pentacene TFT with improved linear region characteristics using chemically modified source and drain electrodes , 2001, IEEE Electron Device Letters.

[12]  D. Natelson,et al.  Nonlinear charge injection in organic field-effect transistors , 2005 .

[13]  Francis Garnier,et al.  Thin-film transistors based on organic conjugated semiconductors , 1998 .

[14]  C. Frisbie,et al.  Temperature and gate voltage dependent transport across a single organic semiconductor grain boundary , 2001 .

[15]  J. A. Nichols,et al.  Potential imaging of pentacene organic thin-film transistors , 2003 .

[16]  Thomas N. Jackson,et al.  Improved organic thin film transistor performance using chemically modified gate dielectrics , 2001, SPIE Optics + Photonics.

[17]  Vladislav Cápek,et al.  Organic molecular crystals : interaction, localization, and transport phenomena , 1994 .

[18]  Thomas N. Jackson,et al.  Modeling of organic thin film transistors of different designs , 2000 .

[19]  B. Batlogg,et al.  Hole mobility in organic single crystals measured by a flip-crystal field-effect technique , 2004 .

[20]  C. Frisbie,et al.  Point contact current–voltage measurements on individual organic semiconductor grains by conducting probe atomic force microscopy , 2000 .

[21]  H. Klauk,et al.  Contact resistance in organic thin film transistors , 2001 .

[22]  D. Schroder.  Semiconductor Material and Device Characterization , 1990 .

[23]  H. Sirringhaus,et al.  Noncontact potentiometry of polymer field-effect transistors , 2002 .

[24]  Michael S. Shur,et al.  Physics of amorphous silicon based alloy field‐effect transistors , 1984 .

[25]  Ute Zschieschang,et al.  Organic electronics on paper , 2004 .

[26]  Thomas N. Jackson,et al.  Contact resistance extraction in pentacene thin film transistors , 2003 .

[27]  J. Shaw,et al.  Simulations of short‐channel and overlap effects in amorphous silicon thin‐film transistors , 1989 .

[28]  J. Park,et al.  Energy level alignment and two-dimensional structure of pentacene on Au(111) surfaces , 2002 .

[29]  C. D. Sheraw,et al.  Organic thin-film transistor-driven polymer-dispersed liquid crystal displays on flexible polymeric substrates , 2002 .

[30]  Xiaoyang Zhu,et al.  Pi-stacked pentacene thin films grown on Au(111) , 2003 .

[31]  H. Grubin.  The physics of semiconductor devices , 1979, IEEE Journal of Quantum Electronics.

[32]  P. Ruden,et al.  Investigation of bottom-contact organic field effect transistors by two-dimensional device modeling , 2003 .

[33]  Raoul Schroeder,et al.  Improving organic transistor performance with Schottky contacts , 2004 .

[34]  Thomas N. Jackson,et al.  Pentacene organic thin-film transistors for circuit and display applications , 1999 .

[35]  P. Ruden,et al.  Channel formation in organic field-effect transistors , 2002 .

[36]  Gerold W. Neudeck,et al.  An experimental study of the source/drain parasitic resistance effects in amorphous silicon thin film transistors , 1992 .

[37]  Thomas N. Jackson,et al.  Ion-beam-deposited ultrathin transparent metal contacts , 2000 .

[38]  C. Frisbie,et al.  Variable temperature film and contact resistance measurements on operating n-channel organic thin film transistors , 2004 .

[39]  Sampath Purushothaman,et al.  High-performance bottom electrode organic thin-film transistors , 2001 .

[40]  C. Daniel Frisbie,et al.  Potentiometry of an operating organic semiconductor field-effect transistor , 2001 .

[41]  Michael A. Haase,et al.  Pentacene-based radio-frequency identification circuitry , 2003 .

[42]  T. Jackson,et al.  Pentacene organic thin-film transistors-molecular ordering and mobility , 1997, IEEE Electron Device Letters.

[43]  J. C. Scott,et al.  Metal–organic interface and charge injection in organic electronic devices , 2003 .

[44]  J. A. Nichols,et al.  Analog and digital circuits using organic thin-film transistors on polyester substrates , 2000, IEEE Electron Device Letters.

[45]  B. Batlogg,et al.  Field-induced charge transport at the surface of pentacene single crystals: A method to study charge dynamics of two-dimensional electron systems in organic crystals , 2003 .

[46]  A. Carlo,et al.  Influence of carrier mobility and contact barrier height on the electrical characteristics of organic transistors , 2002 .

[47]  Norbert Koch,et al.  Organic molecular films on gold versus conducting polymer: Influence of injection barrier height and morphology on current–voltage characteristics , 2003 .

[48]  Richard H. Friend,et al.  Close look at charge carrier injection in polymer field-effect transistors , 2003 .

[49]  C. Daniel Frisbie,et al.  Gated four-probe measurements on pentacene thin-film transistors: Contact resistance as a function of gate voltage and temperature , 2004 .

[50]  Robert A. Street,et al.  Pentacene thin film transistors on inorganic dielectrics: Morphology, structural properties, and electronic transport , 2003 .

[51]  C. Dimitrakopoulos,et al.  Organic Thin Film Transistors for Large Area Electronics , 2002 .

[52]  Feng Gao,et al.  Large area, high resolution, dry printing of conducting polymers for organic electronics , 2003 .

[53]  T. Jackson,et al.  Solvent-induced phase transition in thermally evaporated pentacene films , 1999 .

[54]  C. Daniel Frisbie,et al.  Surface potential profiling and contact resistance measurements on operating pentacene thin-film transistors by Kelvin probe force microscopy , 2003 .