access icon free Design of a voltage-programmed V TH compensating pixel circuit for AMOLED displays using diode-connected a-IGZO TFT

This study presents a novel voltage-programmed, amorphous-indium–gallium–zinc oxide (a-IGZO) thin-film transistor (TFT)-based active-matrix organic light-emitting diode (AMOLED) pixel circuit. The circuit utilises the threshold voltage (V TH) sensing ability of a diode-connected transistor to compensate for the spatial as well as the temporal variation of the threshold voltage of the driving transistor and supply a constant current to the OLED. The circuit has been simulated in Cadence Spectre using a-IGZO TFT and OLED simulation program with integrated circuit emphasis (SPICE) models, and the analysis is presented to prove the V TH compensating capability of the proposed circuit. For small currents, about 50nA, the error is suppressed to <9% whereas for large currents, about 2.5 µA, the error is only 1.05%. This performance has been achieved using only five TFTs and two storage capacitors.

Inspec keywords: amorphous semiconductors; capacitors; SPICE; thin film transistors; LED displays; gallium compounds; zinc compounds; organic light emitting diodes; indium compounds

Other keywords: amorphous-indium–gallium–zinc oxide thin-film transistor-based active-matrix organic light-emitting diode pixel circuit; voltage-programmed VTH compensating pixel circuit; InGaZnO; diode-connected a-IGZO TFT; threshold voltage sensing ability; AMOLED displays; driving transistor; Cadence Spectre; OLED SPICE models; storage capacitors

Subjects: Display technology; Other field effect devices; Semiconductor device modelling, equivalent circuits, design and testing; Capacitors; Light emitting diodes

References

    1. 1)
      • 7. Chen, C., Abe, K., Kumomi, H., et al: ‘A-InGaZnO thin-film transistors for AMOLEDs: electrical stability and pixel-circuit simulation’, J. Soc. Inf. Disp., 2009, 17, (6), pp. 525534.
    2. 2)
      • 16. Kandpal, K., Gupta, N.: ‘Adaptation of a compact SPICE level 3 model for oxide thin-film transistors’, J. Comput. Electron., 2019, 18, (3), pp. 10371044.
    3. 3)
      • 4. Dawson, R.M.A., Shen, Z., Furst, D.A., et al: ‘The impact of the transient response of organic light emitting diodes on the design of active matrix OLED displays’. Int. Electron Devices Meeting 1998, Technical Digest (Cat. No. 98CH36217), San Francisco, California, USA, 1998, pp. 875878.
    4. 4)
      • 2. Lee, J.-H., Kim, J.-H., Han, M.-K.: ‘A new a-Si: H TFT pixel circuit compensating the threshold voltage shift of a-Si: H TFT and OLED for active matrix OLED’, IEEE Electron. Device Lett.., 2005, 26, (12), pp. 897899.
    5. 5)
      • 19. Song, E., Nam, H.: ‘Novel voltage programming n-channel TFT pixel circuit for low power and high performance AMOLED displays’, Displays, 2014, 35, (3), pp. 118125.
    6. 6)
      • 12. Jeon, C.H., Um, J.G., Mativenga, M., et al: ‘Fast threshold voltage compensation AMOLED pixel circuit using secondary gate effect of dual gate a-IGZO TFTs’, IEEE Electron. Device Lett.., 2016, 37, (11), pp. 14501453.
    7. 7)
      • 5. Nathan, A., Striakhilev, D., Chaji, R., et al: ‘Backplane requirements for active matrix organic light emitting diode displays’. MRS Online Proc. Library Archive, San Francisco, California, USA, 2006, vol. 910.
    8. 8)
      • 9. Wu, C.-H., Chang, K.-M., Huang, S.-H., et al: ‘Characteristics of IGZO TFT prepared by atmospheric pressure plasma jet using PE-ALD Al2O3 gate dielectric’, IEEE Electron. Device Lett.., 2012, 33, (4), pp. 552554.
    9. 9)
      • 6. Sanal, K.C., Majeesh, M., Jayaraj, M.K.: ‘Growth of IGZO thin films and fabrication of transparent thin film transistor by RF magnetron sputtering’. Nanostructured Thin Films VI, San Diego, California, USA, 2013, p. 881814.
    10. 10)
      • 13. Jankovic, N.D., Brajovic, V.: ‘Vth compensated AMOLED pixel employing dual-gate TFT driver’, Electron. Lett., 2011, 47, (7), pp. 456457.
    11. 11)
      • 10. Powell, M.J., Nicholls, D.H.: ‘Stability of amorphous-silicon thin-film transistors’, IEE Proc. I (Solid-State Electron Devices), 1983, 130, (1), pp. 24.
    12. 12)
      • 18. Vosniadis, P., Siskos, S.: ‘A new threshold-voltage compensation technique of IGZO and LTPS for AMOLED display pixel circuit’. 2017 Panhellenic Conf. on Electronics and Telecommunications (PACET), Xanthi, Greece, 2017, pp. 14.
    13. 13)
      • 3. Ashtiani, S.J., Chaji, G.R., Nathan, A.: ‘AMOLED pixel circuit with electronic compensation of luminance degradation’, J. Disp. Technol., 2007, 3, (1), pp. 3639.
    14. 14)
      • 1. Lin, C.-L., Chang, W.-Y., Hung, C.-C.: ‘Compensating pixel circuit driving AMOLED display with a-IGZO TFTs’, IEEE Electron. Device Lett.., 2013, 34, (9), pp. 11661168.
    15. 15)
      • 11. Kandpal, K., Gupta, N.: ‘Investigations on high-κ dielectrics for low threshold voltage and low leakage zinc oxide thin-film transistor, using material selection methodologies’, J. Mater. Sci. Mater. Electron., 2016, 27, (6), pp. 59725981.
    16. 16)
      • 17. Lee, J.-M., Cho, I.-T., Lee, J.-H., et al: ‘Bias-stress-induced stretched-exponential time dependence of threshold voltage shift in InGaZnO thin film transistors’, Appl. Phys. Lett., 2008, 93, (9), p. 93504.
    17. 17)
      • 8. Wu, C.-H., Chang, K.-M., Hsu, H.-Y.: ‘High-performance HfO2/ZrO2/IGZO thin-film transistors deposited using atmospheric pressure plasma jet’, Electron. Lett., 2014, 50, (23), pp. 17471749.
    18. 18)
      • 20. Pappas, I., Siskos, S., Dimitriadis, C.: ‘P-31: a new threshold voltage compensation technique of poly-Si TFTs for AMOLED display pixel circuit’. SID Symp. Digest of Technical Papers, 2010, pp. 13361339.
    19. 19)
      • 14. Hsu, C.-C., Wu, C.-H., Ting, W.-C.: ‘Stability improvement of amorphous InGaZnO TFTs by an asymmetric design’, Electron. Lett., 2015, 51, (19), pp. 15341536.
    20. 20)
      • 15. Chaji, R., Nathan, A.: ‘Thin film transistor circuits and systems’ (Cambridge University Press, USA, 2013).
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-cds.2020.0070
Loading

Related content

content/journals/10.1049/iet-cds.2020.0070
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading