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Silicon and Dopant Ink-Based CMOS TFTs on Flexible Steel Foils

Published online by Cambridge University Press:  20 February 2017

Aditi Chandra*
Affiliation:
Thinfilm Electronics, San Jose, CA, 95134United States.
Mao Takashima
Affiliation:
Thinfilm Electronics, San Jose, CA, 95134United States.
Arvind Kamath
Affiliation:
Thinfilm Electronics, San Jose, CA, 95134United States.
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Abstract

Polysilicon complementary metal oxide semiconductor (CMOS) thin film transistors (TFTs) are fabricated on large area, flexible stainless steel foils using novel ink depositions within a hybrid printed/conventional process flow. A self-aligned top gate TFT structure is realized with an additive materials approach to substitute the use of high capital cost ion implantation and lithography processes. Polyhydrosilane-based silicon ink is coated and laser crystallized to form the polysilicon channel. Semiconductor grade P-type and N-type unique dopant ink formulations are screen printed and combined with thermal drive in and activation to form self-aligned doped source and drain regions. A high refractory top gate material is chosen for its process compatibility with printed dopants, chemical resistance, and work function. Steel foil substrates are fully encapsulated to allow for high temperature processing. The resultant materials set and process flow enables TFT electrical characteristics with NMOS and PMOS mobilities exceeding 120 cm2/Vs and 60 cm2/Vs, respectively. On/Off ratios are >107. Reproducibility, uniformity, and reliability data in a production environmental is shown to demonstrate high volume, high throughput manufacturability. The device characteristics and scheme enable NFC (13.56MHz) capable circuits for use in flexible NFC and display-based smart labels and packaging.

Type
Articles
Copyright
Copyright © Materials Research Society 2017 

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References

REFERENCES

Qi, S., Yi, C., Ji, S., Fong, CC., Yang, M., ACS Appl. Mater. Interfaces, 1(1), pp. 30. (2009)Google Scholar
McAline, M. C., Ahmad, H, Wang, D, Heath, JR., Nat. Materials (2007).Google Scholar
Duan, X., Niu, C., Sahi, V., Chen, J., Parce, J. W., Empedocles, S. and Goldman, J. L.,Nature 425, 274278 (18) September (2003).Google Scholar
Shimoda, T., Matsuki, Y., Furusawa, M., Aoki, T., Yudasaka, I., Tanaka, H., Iwasawa, H., Wang, D., Miyasaka, M. and Takeuchi, Y., Nature 440, 783786 (2006).CrossRefGoogle Scholar
Takashima, M., Chandra, A. Kamath, A., Flextech 2015 Proceedings.Google Scholar
Takashima, M., Chandra, A. Kamath, A., SID display week SID Symposium Digest of Technical Papers, 46, 1 (2015)Google Scholar
Takashima, M., Chandra, A. Kamath, A.,, Flexible Hybrid Electronics for Wearable Applications – Challenges and Solutions Semiconwest (2015)Google Scholar
Meier, D. L., Davis, H. P., Hacke, P., Garcia, R. A., Yamanaka, S., Salami, J. and Jessup, J. A., Proceedings 17th EC PVSEC, Munich, Germany, 13231326, 2001.Google Scholar
Rohatgi, A., Hilali, M., Meier, D. L., Ebong, A., Honsberg, C., Carroll, A. F. and Hacke, P., Proceedings 17th EC PVSEC, Munich, Germany, 13071310, 2001.Google Scholar
Hilali, M. M., Rohatgi, A. and Asher, S., IEEE Trans. Electron Dev. Vol. 51(6) 2004, 948955 CrossRefGoogle Scholar