Flexible Hybrid Single-Crystalline Silicon Nanomembrane Thin-Film Transistor with Organic Polymeric Polystyrene as a Gate Dielectric on a Plastic Substrate

Abstract

Flexible thin-film transistors (TFTs) play an important role in flexible integrated circuits (ICs). Hybrid integrated transistors are highly desirable because of their high performance and simplified process. However, TFTs with a hybrid integrated heterostructure of single-crystalline semiconductor/organic dielectric layers have not yet been discussed. In this work, a flexible hybrid TFT comprised of a single-crystalline silicon nanomembrane (SiNM) semiconductor and polystyrene (PS) gate dielectric was fabricated on a PET substrate. The surface morphology of the PS dielectric layer on the PET substrate was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrical characteristics of the dielectric layer (PS) were also analyzed. SiNM was processed with a complementary metal–oxide–semiconductor (CMOS)-compatible process and subsequently transferred to the PET substrate with a PS/ITO stacked layer to complete the assembly of the flexible hybrid SiNM/PS TFT. The electrical properties of the flexible hybrid TFT were characterized under different bending conditions (i.e., flat and bending radii of 21, 38.5, and 77.5 mm). Furthermore, the stress analysis of TFTs influenced by a variation of the dielectric materials (i.e., PS, SiO2, and Al2O3), the adhesion conditions of the SiNM/PS interface, and the dielectric thickness were also discussed. The results revealed the potential of combining an organic polymeric dielectric with inorganic single-crystalline nanomembranes to fabricate high-performance flexible hybrid TFTs.