Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-27T18:36:15.368Z Has data issue: false hasContentIssue false

Amorphous Silicon 2-TFT Pixel Circuits on Stainless Steel Foils

Published online by Cambridge University Press:  01 February 2011

Alex Z Kattamis
Affiliation:
[email protected], Princeton University, Princeton Institute for the Science and Technology of Materials and the Department of Electrical Eng, E-Quad Building, Olden Street, Princeton, NJ, 08544, United States
I-Chun Cheng
Affiliation:
[email protected], Princeton University, Princeton Institute for the Science and Technology of Materials & the Department of Electrical Eng, E-Quad Building, Olden Street, Princeton, NJ, 08544, United States
Yongtaek Hong
Affiliation:
[email protected], Eastman Kodak Company, Display Science & Technology Center, 1999 Lake Road, Rochester, NY, 14626, United States
Sigurd Wagner
Affiliation:
[email protected], Princeton University, Princeton Institute for the Science and Technology of Materials & the Department of Electrical Eng, E-Quad Building, Olden Street, Princeton, NJ, 08544, United States
Get access

Abstract

We have fabricated pixel circuits consisting of two bottom-gate staggered source-drain amorphous silicon thin-film transistors (a-Si:H TFTs) on flexible stainless steel foils. Stainless steel is attractive because it allows for high processing temperatures of >300°C and is a perfect barrier to oxygen and moisture. Our steel foils were 75m thick, with a peak-to-peak surface roughness of >1.2m. This rough, as-rolled, conductive surface needed a thick planarization and passivation (electrical isolation) layer. The surface was planarized with 1.6m of spin-on-glass, which reduced the roughness to ~0.3m peak-to-peak. A passivation layer of 0.6m of SiNx deposited by plasma-enhanced chemical vapor deposition was used to reduce leakage currents and capacitive coupling to the substrate. The 92m × 369m voltage-programmed pixel circuits employ a switching (Sw) TFT (W/L=50/5m), a driver (Dr) TFT (W/L=200/5m), and a 2pF storage capacitor between the gate and source of the Dr TFT. With a supply voltage of VDD=20V and a drive bias of 20V the circuits deliver 26A of current. The vertical stripe pixels were integrated into 48 × (4) × 48 arrays and passivated with SiNx. Anode metal of Al-1% Si was also deposited, preparing the displays for subsequent OLED fabrication. Pixel circuits with this performance can drive top-emitting organic light emitting diodes (OLEDs) and therefore can be used in backplanes for flexible, high-resolution, active-matrix OLED displays.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Cannella, V., Izu, M., Jones, S., Wagner, S., and Cheng, I.-C., Information Display, pp.2427, June, 2005.Google Scholar
[2] Long, K., Kattamis, A. Z., Cheng, I-C., Gleskova, H., Wagner, S. and Sturm, J. C., IEEE Elec Dev Lett., vol. 27, pp. 111113, 2006.Google Scholar
[3] Wu, M., Bo, X., Sturm, J. C., and Wagner, S., IEEE Trans. Elec. Dev., vol. 49, pp. 19932000, 2002.Google Scholar
[4] Theiss, S. D., and Wagner, S., IEEE Elec. Dev. Lett., vol. 17, pp. 578580, 1996.Google Scholar
[5] Hong, Y., Heiler, G., Cheng, I-C., Kattamis, A. Z., Wagner, S., IMID '05 Digest, vol. 28/3, pp. 892896, 2005.Google Scholar
[6] Zaborowski, M., and Dumania, P., Microelec. Eng., vol. 50, pp. 301309, 2000.Google Scholar