The use of solution processes—as opposed to conventional vacuum processes and vapour-phase deposition—for the fabrication of electronic devices has received considerable attention for a wide range of applications1, 2, 3, 4, 5, 6, 7, with a view to reducing processing costs. In particular, the ability to print semiconductor devices using liquid-phase materials could prove essential for some envisaged applications, such as large-area flexible displays. Recent research in this area has largely been focused on organic semiconductors8, 9, 10, 11, some of which have mobilities comparable to that of amorphous silicon11 (a-Si); but issues of reliability remain. Solution processing of metal chalcogenide semiconductors to fabricate stable and high-performance transistors has also been reported12, 13. This class of materials is being explored as a possible substitute for silicon, given the complex and expensive manufacturing processes required to fabricate devices from the latter. However, if high-quality silicon films could be prepared by a solution process, this situation might change drastically. Here we demonstrate the solution processing of silicon thin-film transistors (TFTs) using a silane-based liquid precursor. Using this precursor, we have prepared polycrystalline silicon (poly-Si) films by both spin-coating and ink-jet printing, from which we fabricate TFTs with mobilities of 108 cm2 V-1 s-1 and 6.5 cm2 V-1 s-1, respectively. Although the processing conditions have yet to be optimized, these mobilities are already greater than those that have been achieved in solution-processed organic TFTs, and they exceed those of a-Si TFTs ( 1 cm2 V-1 s-1).
Technology Platform Research Centre, Seiko Epson Corporation, 281 Fujimi, Fujimi-machi, Nagano-ken, 399-0293 Japan
Fine Electronic Research Laboratories, JSR Corporation, 100 Kawajiri-cho, Yokkaichi, Mie, 510-8552 Japan
†Present address: International Centre for Material Research, 1-1 Minamiwataridacho, Kawasaki-ku, Kawasaki-city, Kanagawa, 210-0855 Japan