(Invited) Printed Poly-Si TFTs on Paper for Beyond Plastic Electronics

Silicon can be printed using liquid silicon ink, which is a mixture of polymerized cyclopentasilane (CPS) and a solvent. Thermal annealing higher than 350oC of this material, however, was necessary, to convert it to solid silicon, which prevented its usage on inexpensive substrates with a limited thermal budget. We review a novel method that forms polycrystalline silicon (poly-Si) patterns directly on paper using the same liquid silicon with doctor-blade coating and local irradiation of excimer-laser with room temperature process. We review also the process and electrical properties of poly-Si TFTs fabricated on the paper. This technique will breakthrough the printed electronics by enabling applications such as fast printed electronics that are inexpensive, fully-recyclable, biodegradable and even edible.