High-performance full-swing a-HfInZnO inverter and advanced integrated logic circuits

Abstract

We report the fabrication and characterization of high-performance, full-swing inverter and logic circuits based on amorphous hafnium-indium-zinc-oxide (a-HIZO) thin film transistors (TFTs) with varying channel layer thicknesses. Structural and compositional analyses were performed to validate the amorphous nature and chemical uniformity of the HIZO matrix. High-resolution transmission electron microscopy (HRTEM) confirmed the absence of crystallinity. Energy-dispersive X-ray spectroscopy (STEM-EDX) elemental mapping revealed homogeneous distribution of Hf, In, Zn, and O, supporting the multicomponent oxide system. X-ray photoelectron spectroscopy (XPS) analysis was conducted to investigate the elemental composition and oxidation states of Hf, In, Zn, and O. The transmission line method (TLM) was utilized to ensure ohmic contact between the electrodes and the channel layer, and to calculate total resistance, sheet resistance, and contact resistance. The TFTs demonstrated excellent electrical performance, including a maximum field-effect mobility of 13.5 ${\mathrm{cm}}^2{V}^{-1}{s}^{-1}$, an on/off current ratio of 10${}^8$, and stable operation under temperature stress. The a-HIZO-based inverters achieved a maximum voltage gain of 32.38 at a supply voltage of 16 V. In addition, logic circuits, such as NOR and NAND gates, were fabricated, showcasing sharp transfer characteristics. These results highlight the potential of a-HIZO TFTs for advanced electronic applications.