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Novel back‐channel‐etch process flow based a‐IGZO TFTs for circuit and display applications on PEN foil
Author(s) -
Nag Manoj,
Rockele Maarten,
Steudel Soeren,
Chasin Adrian,
Myny Kris,
Bhoolokam Ajay,
Willegems Myriam,
Smout Steve,
Vicca Peter,
Ameys Marc,
Ke Tung Huei,
Schols Sarah,
Genoe Jan,
Steen JanLaurens P. J.,
Groeseneken Guido,
Heremans Paul
Publication year - 2013
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1002/jsid.189
Subject(s) - thin film transistor , materials science , optoelectronics , amoled , foil method , threshold voltage , oled , backplane , transistor , voltage , active matrix , electrical engineering , nanotechnology , layer (electronics) , composite material , engineering
In this study, we report high‐quality amorphous indium–gallium–zinc‐oxide (a‐IGZO) thin‐film transistors (TFTs) fabricated on a polyethylene naphthalate foil using a new back‐channel‐etch (BCE) process flow. The BCE flow allows a better scalability of TFTs for high‐resolution backplanes and related circuits. The maximum processing temperature was limited to less than 165 °C in order to ensure good overlay accuracy (<1 µm) on foil. The presented process flow differs from the previously reported flow as we define the Mo source and drain contacts by dry etch prior to a‐IGZO patterning. The TFTs show good electrical performance, including field‐effect mobilities in the range of 15.0 cm 2 /(V·s), subthreshold slopes of 0.3 V/decade, and off‐currents <1.0 pA on foil. The threshold voltage shifts of the TFTs measured were less than 1.0 V after a stressing time of 10 4 s in both positive (+1.0 MV/cm) and negative (−1.0 MV/cm) bias directions. The applicability of this new BCE process flow is demonstrated in a 19‐stage ring oscillator, demonstrated to operate at a supply voltage of 10 V with a stage delay time of 1.35 µs, and in a TFT backplane driving a 32 × 32 active‐matrix organic light‐emitting diode display.