Circuits and AMOLED display with self‐aligned a‐IGZO TFTs on polyimide foil. Issue 10 (13th April 2015)

• Record Type: Journal Article
• Authors: Nag, Manoj; Bhoolokam, Ajay; Smout, Steve; Willegems, Myriam; Muller, Robert; Myny, Kris; Schols, Sarah; Ameys, Marc; Genoe, Jan; Ke, Tung Huei; Vicca, Peter; Ellis, Tim; Cobb, Brian; Kumar, Abhishek; van der Steen, Jan‐Laurens P. J.; Gelinck, Gerwin; Fukui, Yusuke; Obata, Koji; Groeseneken, Guido; Heremans, Paul; Steudel, Soeren
• Is Part Of: Journal of the Society for Information Display. Volume 22:Issue 10(2014:Oct.)
• Page Start: 509
• Page End: 517
• Publication Date: 2015-04-13
• Subjects: Information display systems -- Periodicals; 621.38154205
• DOI: 10.1002/jsid.281
• Languages: English
• ISSNs: 1071-0922

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>A process to make self‐aligned top‐gate amorphous indium‐gallium‐zinc‐oxide (a‐IGZO) thin‐film transistors (TFTs) on polyimide foil is presented. The source/drain (S/D) region's parasitic resistance reduced during the SiN interlayer deposition step. The sheet resistivity of S/D region after exposure to SiN interlayer deposition decreased to 1.5 kΩ/□. TFTs show field‐effect mobility of 12.0 cm²/(V.s), sub‐threshold slope of 0.5 V/decade, and current ratio (<italic>I</italic>_{<italic>ON</italic>/<italic>OFF</italic>}) of &gt;10⁷. The threshold voltage shifts of the TFTs were 0.5 V in positive (+1.0 MV/cm) bias direction and 1.5 V in negative (−1.0 MV/cm) bias direction after extended stressing time of 10⁴ s. We achieve a stage‐delay of ~19.6 ns at <italic>V_DD</italic> = 20 V measured in a 41‐stage ring oscillator. A top‐emitting quarter‐quarter‐video‐graphics‐array active‐matrix organic light‐emitting diode display with 85 ppi (pixels per inch) resolution has been realized using only five lithographic mask steps. For operation at 6 V supply voltage (<italic>V_DD</italic>), the brightness of the display exceeds 150 cd/m².</p> </abstract>