Meniscus-force-mediated layer transfer technique using single-crystalline silicon films with midair cavity: Application to fabrication of CMOS transistors on plastic substrates

Abstract

A novel low-temperature technique for transferring a silicon-on-insulator (SOI) layer with a midair cavity (supported by narrow SiO2 columns) by meniscus force has been proposed, and a single-crystalline Si (c-Si) film with a midair cavity formed in dog-bone shape was successfully transferred to a poly(ethylene terephthalate) (PET) substrate at its heatproof temperature or lower. By applying this proposed transfer technique, high-performance c-Si-based complementary metal–oxide–semiconductor (CMOS) transistors were successfully fabricated on the PET substrate. The key processes are the thermal oxidation and subsequent hydrogen annealing of the SOI layer on the midair cavity. These processes ensure a good MOS interface, and the SiO2 layer works as a “blocking” layer that blocks contamination from PET. The fabricated n- and p-channel c-Si thin-film transistors (TFTs) on the PET substrate showed field-effect mobilities of 568 and 103 cm2 V−1 s−1, respectively.

Single-Crystalline Si-CMOS Circuit Fabrication on Polyethylene Terephthalate Substrate by Meniscus Force-Mediated Layer Transfer

“…Recently, we proposed a water-induced meniscus forcemediated layer transfer (MLT) technique. The MLT technique enables the direct transfer of sc-Si islands onto the SOI wafer, which are supported by SiO 2 pillars formed by buried-oxide (BOX) layer etching, to polyethylene terephthalate (PET) or glass substrates without requiring adhesive layer mediation at a process temperature below 130 • C [23]- [26]. Strong adhesion between the transferred sc-Si island and the PET substrate was obtained by the Si-O-C bonds that are induced by dehydrogenative condensation and by the glass phase transition of the PET substrate [27].…”