Abstract
This paper presents an investigation on the design of organic thin-film transistors (OTFTs) with short channel lengths required to achieve higher integration density organic circuits for various DC and RF applications. The DC and AC performance parameters of an OTFT with channel lengths 5, 2, 1.5, 1.0, 0.9 and 0.7 \(\upmu \hbox {m}\) have been evaluated through carefully calibrated two-dimensional numerical simulation. The designed OTFT uses pentacene as the active layer in the bottom-contact configuration. The various performance parameter metrics, i.e., threshold voltage (\({V}_\mathrm{TH}\)), transconductance (\({G}_\mathrm{M}\)), gain (\({A}_\mathrm{V}\)), I\(_\mathrm{ON}\)/I\(_\mathrm{OFF}\), DIBL, cutoff frequency (\({f}_\mathrm{T}\)) and breakdown voltage (\({V}_\mathrm{BR}\)), have been evaluated. The results have revealed that OTFTs with short channel lengths show improved performance compared to long channel transistors. The second-order effects of V\(_\mathrm{TH}\) roll-off and DIBL are less pronounced in OTFTs. Results show that the \(\mathrm{V}_\mathrm{TH}\) reduces only by 10.73% from \(L=5\,\upmu \hbox {m}\) to \(L=0.7 \,\upmu \hbox {m}\). The results have shown that OTFTs have a high I\(_\mathrm{ON}\)/I\(_\mathrm{OFF}\) ratio of the order of 10\(^{13}\) and thus are effective for fast switching applications. The cutoff frequency of the simulated device for \(L=0.7\,\upmu \) m is 2.3 GHz suggesting the application of OTFTs for RF applications. The role of trap states on the device conduction has also been investigated. The simulation study has revealed that OTFTs exhibit well-defined mobility degradation and impact ionization behavior which becomes pronounced for channel lengths below 1 \(\upmu \hbox {m}\). Further the capacitive behavior of the designed device has been evaluated, and it has been observed that the device capacitance can be defined from the MOSFET theory except for the role of trap states.
Similar content being viewed by others
References
Forrest, S.R.: The path to ubiquitous and low-cost organic electronic appliances on plastic. Nature 428, 911–918 (2004)
Pray, L.A.: Organic electronics for a better tomorrow: innovation, accessibility, sustainability. Royal Society of Chemistry, http://www.rsc.org/globalassets/04-campaigning-outreach/policy/research-policy/global-challenges/organic-electronics-for-a-better-tomorrow.pdf, April 08 (2013)
Reese, C., Roberts, M., Ling, M., Bao, Z.: Organic thin film transistors. Mater. Today 7(9), 20–27 (2004)
Wondmagegn, W., Pieper, R.: Simulation of top-contact pentacene thin film transistor. J. Comput. Electron. 8, 19–24 (2009)
Shekar, C., Lee, T., Rhee, S.W.: Organic thin film transistors, materials, processes and devices. Korean J. Chem. Eng. 21, 267–287 (2004)
Klauk, H., Halik, M., Zschieschang, U., Schmid, G., Radlik, W.: High-mobility polymer gate dielectric pentacene thin film transistors. J. Appl. Phys. 92, 5259 (2002)
Mittal, P., Yadav, A., Negi, Y.S., Singh, R.K., Tripathi, N.: Parameter extraction and analysis of pentacene thin film transistor with different insulators. In: Proceedings of the International Conference on Advances in Electronics, Electrical and Computer Science Engineering- EEC (2012)
Gupta, D., Katiyar, M., Gupta, D.: An analysis of the difference in behavior of top and bottom contact organic thin film transistors using device simulation. Org. Electron. 10, 775–784 (2009)
Necliudov, P.V., Shur, M.S., Gundlach, D.J., Jackson, T.N.: Modeling of organic thin film transistors of different designs. J. Appl. Phys. 88, 6594 (2000)
Garnier, F., Hajlaoui, R., Yasser, A., Srivastava, P.: All polymer field-effect transistors realized by printing techniques. Science 265, 1684 (1994)
Mittal, P., Kumar, B., Negi, Y.S., Kaushik, B.K., Singh, R.K.: Channel length variation effect on performance parameters of organic field effect transistors. Microelectron. J. 43, 985–994 (2012)
Locci, S., Morana, M., Orgiu, E., Bonfiglio, A., Lugli, P.: Modeling of short-channel effects in organic thin-film transistors. IEEE Trans. Electron Devices 55, 2561–2567 (2008)
Torsi, L., Dodabalapur, A., Katz, H.E.: An analytical model for short channel organic thinfilm transistors. J. Appl. Phys. 78, 1088 (1995)
Gupta, D., Jeon, N., Yoo, S.: Modeling the electrical characteristics of TIPS-pentacene thin-film transistors: effect of contact barrier, field-dependent mobility, and traps. Org. Electron. 9, 1026–1031 (2008)
Sharma, A., Yadav, S., Kumar, P., Chaudhuri, S.R., Ghosh, S.: Defect states and their energetic position and distribution in organic molecule semiconductors. Appl. Phys. Lett. 102, 143301 (2013)
Stallinga, P., Gomes, H.L.: Thin-film field-effect transistors: the effects of traps on the bias and temperature dependence of field-effect mobility, including the Meyer-Neldel rule. Org. Electron. 7, 592–599 (2006)
Ana, F., Najeeb-ud, D.: Simulation study of the electrical behavior of bottom contact organic thin-film transistor’s. IEEE Xplore. https://doi.org/10.1109/ICEmElec.2014.7151133
Ana, F., Najeeb-ud, D.: Effect of mobility degradation on the device performance of organic thin-film transistor’s. IEEE Xplore. https://doi.org/10.1109/TENCON.2016.7848654
Mottaghi, M., HorowitzI, G.: Field-induced mobility degradation in pentacene thin-film transistors. Org. Electron. 7, 445–606 (2006)
Braga, D., Horowitz, G.: Subthreshold regime in rubrene single-crystal organic transistors. Appl. Phys. A Mater. Sci. Process. 95, 193–201 (2009)
Streetman, B.G., Banerjee, S.: Solid State Electronic Devices, 6th Edition. Printice Hall, London.
Mittal, P., Negi, Y.S., Singh, R.K.: Impact of source and drain contact thickness on the performance of organic thin film transistors. J. Semicond. 35, 124002 (2014)
Klauk, H., Zschieschang, U.: Low-voltage organic thin-film transistors with large transconductance. J. Appl. Phys. 102, 074514 (2007)
Yaglioglu, B., Agostinelli, T., Cain, P., Mijalkovic, S., Nejim, A.: Parameter extraction and evaluation of UOTFT model for organic thin-film transistor circuit design. J. Disp. Technol. 9, 890–894 (2013)
Anand, S., Amin, S.I., Sarin, R.K.: Analog performance investigation of dual electrode based doping-less tunnel FET. J. Comput. Electron. (2015)
Tang, Z., Wie, C.R.: Capacitance-voltage characteristics and device simulation of bias temperature stressed a-Si: H TFTs. Solid-State Electron. 54, 259–267 (2009)
Weste, N.H.E., Harris, D., Banerjee, A.: CMOS VLSI Design: A Circuits and Systems Perspective, 3rd edition. Pearson Education Asia (2006)
Zaki, T., Rodel, R., Letzkus, F., Richter, H., Zschieschang, U., Klauk, H., Burghartz, J.N.: AC characterization of organic thin-film transistors with asymmetric gate-to-source and gate-to-drain overlaps. Org. Electron. 14, 1318–1322 (2013)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ana, F., Din, Nu. Design and performance investigation of short channel bottom-contact organic thin-film transistors. J Comput Electron 17, 1315–1323 (2018). https://doi.org/10.1007/s10825-018-1170-4
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10825-018-1170-4