Digital-lithographic processing for thin-film transistor array fabrication
Conventional methods for materials processing, such as thin-film deposition and photolithographic patterning provide the foundation for device fabrication in the microelectronic industry. Although these methods are scaleable and cost-effective, as demonstrated in the silicon integrated-circuit industry, they are not always the most appropriate methods for applications where further miniaturization is not an advantage, such as large-area electronics. For example, the fabrication of flat panel displays and image sensors, with a typical feature size of ~ 50 microns, do not require an expensive and complex photolithographic process. Similarly, the processing of large-area platforms is relatively complex and expensive with conventional vacuum deposition methods. Developing an alternative inexpensive and simplified deposition process in conjunction with an alternative patterning method would enable low-cost, large-area electronics for displays and sensors in addition to evolving technologies such as electric paper. The spatial resolution and small drop volume of direct-write methods present opportunities to simplify and reduce the cost for conventional large-area electronic device fabrication. In this talk, I will describe how direct-writing techniques such as jet printing can be used as a viable alternative to conventional thin-film deposition and photolithographic processes. A novel digital-lithographic method, in which a patterned layer is generated by direct writing, was used to fabricate hydrogenated amorphous silicon thin-film transistor (TFT) arrays. Device characteristics for a-Si:H TFTs fabricated by digital lithography will be presented and compared to devices created by conventional methods.
Wong, W. S. ; Paul, K. ; Street, R. A. Digital-lithographic processing for thin-film transistor array fabrication. Proceedings of the 20th International Conference on Amorphous and Microcrystalline Semiconductors. 2003 August 24-29; Campos do Jordão; Brazil.(to be published in Journal of Noncrystalline Solids)