Slot-die coating of silicon ink for volume production of CMOS polysilicon TFTs

A large-area polysilicon film was formed from slot-die coating of cyclopentasilane based silicon ink and laser crystallization. In this article a study of silicon ink preparation and selection, slot-die coater setup, coating and laser crystallization is described. The polysilicon film was applied to fabricate complementary metal oxide semiconductor (CMOS) thin film transistors (TFTs) which were used to develop and demonstrate near field communication devices. This was part of a hybrid process flow consisting of conventional lithography and printing to fabricate CMOS TFTs. Slot-die coating of silicon ink on a 300 mm square 100 μm thick stainless steel substrate is a key building block of this hybrid process flow to subtract and replace high capital cost plasma enhanced chemical vapor deposition (PECVD), ion implantation and silicon wafers. With slot-die coating of silicon ink, a silicon layer formation equivalent to PECVD in quality was achieved.