The temperature dependence thermal conductivity of the indium-gallium-zinc oxide (IGZO) thin films was investigated with the differential three-omega method for the clear demonstration of nanocrystallinity. The thin films were deposited on an alumina (α-Al₂O₃) substrate by direct current (DC) magnetron sputtering at different oxygen partial pressures ([PO₂] = 0%, 10%, and 65%). Their thermal conductivities at room temperature were measured to be 1.65, 1.76, and 2.58 Wm⁻¹K⁻¹, respectively. The thermal conductivities decreased with an increase in the ambient measurement temperature. This thermal property is similar to that of crystalline materials. Electron microscopy observations revealed the presence of nanocrystals embedded in the amorphous matrix of the IGZO films. The typical size of the nanocrystals was approximately 2–5 nm with the lattice distance of about 0.24–0.26 nm. These experimental results indicate that the nanocrystalline microstructure controls the heat conduction in the IGZO films.

The electrical performance of the back-channel etched Indium–Gallium–Zinc–Oxide (IGZO) thin-film transistors (TFTs) with copper (Cu) source and drain (S/D) which are patterned by a selective etchant was investigated. The Cu S/D were fabricated on a molybdenum (Mo) layer to prevent the Cu diffusion to the active layer (IGZO). We deposited the Cu layer using thermal evaporation and performed the selective wet etching of Cu using a non-acidic special etchant without damaging the IGZO active layer. We fabricated the IGZO TFTs and compared the performance in terms of linear and saturation region mobility, threshold voltage and ON current (I_ON). The IGZO TFTs with Mo/Cu S/D exhibit good electrical properties, as the linear region mobility is 12.3 cm²/V-s, saturation region mobility is 11 cm²/V-s, threshold voltage is 1.2 V and I_ON is 3.16 × 10⁻⁶ A. We patterned all the layers by a photolithography process. Finally, we introduced a SiO₂-ESL layer to protect the device from external influence. The results show that the prevention of Cu and the introduced ESL layer enhances the electrical properties of IGZO TFTs.

The electrical performance of the back-channel etched Indium–Gallium–Zinc–Oxide (IGZO) thin-film transistors (TFTs) with copper (Cu) source and drain (S/D) which are patterned by a selective etchant was investigated. The Cu S/D were fabricated on molybdenum (Mo) layer to prevent the Cu diffusion to the active layer (IGZO). We deposited the Cu layer using thermal evaporation and performed the selective wet etching of Cu using non-acidic special etchant without damaging the IGZO active layer. We fabricated the IGZO TFTs and compare the performance in terms of linear and saturation region mobility, threshold voltage and ON current (ION). The IGZO TFTs with Mo/Cu S/D exhibits good electrical properties as the linear region mobility is 12.3 cm2/V-s, saturation region mobility is 11 cm2/V-s, threshold voltage is 1.2 V and ION is 3.16 x 10-6 A. We patterned all the layers by photolithography process. Finally, we introduced SiO2-ESL layer to protect the device from the external influence. The results show that the prevention of Cu and introduced ESL layer enhances the electrical properties of IGZO TFTs.

This study introduces an innovative experimental method that combines real-time heating and three-dimensional (3D) observation techniques to examine the sintering process of copper nanoparticles (Cu NPs) using scanning transmission electron microscopy (STEM). This study visualizes the time-resolved 3D dynamics through in situ heating and electron tomography (ET), minimizing contamination by employing a novel MEMS-based heating holder and optimized high-resolution time-resolved 3D data acquisition. Cu NPs (approximately 150 nm in diameter) were suspended in ethanol, placed on MEMS heating chips within an argon-filled glove box, and transferred to TEM without exposure to air. Low-dose HAADF-STEM imaging was used to minimize beam-induced damage and contamination. The block-matching and 3D filtering (BM3D) method was utilized for eliminating noise from images, and the iterative series reduction (ISER) method was employed in order to make certain that the 3D reconstruction was accurate. In situ two-dimensional (2D) observations indicated neck development and grain densification with rising temperatures, whereas three-dimensional (3D) reconstructions provided quantitative measurements of neck width, interparticle distances, particle radii, and aspect ratios. This study illustrates how sophisticated imaging techniques can help us understand nanoscale sintering dynamics, provide us with insightful experimental data for computational models, and set up a solid framework for investigating nanoscale material properties.