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.

Facile Direct Printing of DPP-Based Polymers for Organic Field-Effect Transistors and Logic Gates

“…Commonly used inorganic dielectric layers have the advantages of high capacitance and stability, but they are not suitable for flexible electronics due to their brittle properties and fabrication processes (e.g., temperature treatment) incompatible with plastic substrates. 42,43 Also, the hydroxyl groups on the surface of the oxide dielectric layer can act as charge carrier traps and require additional surface treatment. 44,45 Therefore, we used a polyvinylidene fluoride (PVDF) polymer dielectric in solution-processed OFETs.…”

“…To utilize the good solution-processability of P29DPP-TT, which enables the fabrication of flexible devices, the OFETs with flexible polymer dielectric layers were fabricated using the EHD jet printing technique. Commonly used inorganic dielectric layers have the advantages of high capacitance and stability, but they are not suitable for flexible electronics due to their brittle properties and fabrication processes (e.g., temperature treatment) incompatible with plastic substrates. , Also, the hydroxyl groups on the surface of the oxide dielectric layer can act as charge carrier traps and require additional surface treatment. , Therefore, we used a polyvinylidene fluoride (PVDF) polymer dielectric in solution-processed OFETs. A small amount of cross-linker, fluorophenyl azide-4F (FPA-4F), , was added to the PVDF polymer to cross-link the PVDF polymer and reduce hysteresis and leakage current (Figure S8).…”

Reducing Contact Resistance in Organic Field-Effect Transistors: A Comprehensive Comparison between 2D and Microrod Single Crystals

“…By carefully snapping the substrate upside down to the glycerol surface (Figure S1) and slowly removing glycerol followed by rinsing with ultrapure water, the self-assembled microrod single crystals could be transferred onto the PS-coated silicon substrate. The absence of polar groups on the PS surface is beneficial to the passivation of the defects on SiO 2 , which will improve the quantity of the semiconductor/dielectric interface and accordingly the carrier transport in the conducting channel. , …”

“…The absence of polar groups on the PS surface is beneficial to the passivation of the defects on SiO 2 , which will improve the quantity of the semiconductor/dielectric interface and accordingly the carrier transport in the conducting channel. 26,27 On the other hand, 2D single crystals can be obtained in the same procedure except that the solvent was changed to toluene and amphoteric sodium perfluorooctanoate (1.0 mg/L) was added as a surfactant. As shown in Figure 1e, similarly, when the above solution was dropped on the glycerol surface, thin and large-area 2D single crystals gradually grew to the millimeter scale after 8 h, which could be successfully transferred to the PS-coated silicon substrate using the aforementioned method.…”

Nanolaminated HfO2/Al2O3 Dielectrics for High‐Performance Silicon Nanomembrane Based Field‐Effect Transistors on Biodegradable Substrates

“…[ 4 ] Organic semiconductors have been combined with polymer substrates to yield flexible, stretchable, and biodegradable systems, [ 5 ] while the modest carrier mobilities of organic active materials limit the performance that can be achieved. [ 6 ] Of the various bioresorbable materials employed in the most sophisticated biomedical systems, device‐grade, monocrystalline silicon (Si) is of great interest owing to its potential to act as the basis for flexible high‐performance transistors that align with conventional complementary metal‐oxide‐semiconductor (CMOS) technologies, [ 7 ] while forming minimally invasive interfaces to the soft and dynamic surfaces of targeted biological systems. [ 1h,3b,8 ] Moreover, high‐quality inorganic dielectrics, including silicon dioxide (SiO 2 ) and magnesium oxide (MgO) generally serve as the biodegradable gate dielectric materials in Si nanomembrane (NM) based transient microsystems.…”