Development of Thin-Film Transistors Using Liquid Silicon

Abstract

In this chapter, several kinds of thin-film transistors (TFTs) from liquid silicon are introduced. The TFT, described in Sect. 10.1, came from our first published work related liquid silicon, which appeared just before the JST-ERATO project had started. We were able to show the feasibility of making poly-Si films from liquid silicon equivalent to the conventional counterparts, i.e., solid- and gas-based ones. The TFTs using liquid-processed poly-Si films as a channel exhibited as high performance as those using gas phase-deposited ones. In this work we also demonstrated ink-jet printing of a channel for a poly-Si TFT.

As the second example, we introduce the TFTs which have been developed by Professor Ishikawa’s group in Delft University of Technology under collaboration of our team. They applied their original technique called micro-Czochralski method for solution-processed TFTs and fabricated a single-grained TFT which exhibited a mobility as high as that of a typical MOS-FET. A single-grained TFT was also obtained on a plastic substrate. Those TFTs are described in Sect. 10.2. Subsequently they succeeded to fabricate a TFT via an ultralow temperature process by developing an elaborate solidification process of liquid silicon. That actually enabled them to make a TFT on paper. That is described in Sect. 10.3.