Thermal atomic layer deposition-processed InHfZnO thin film transistors with excellent stability

In recent years, the downscaling of transistors has sparked considerable interest in the advancement of amorphous oxide semiconductors, particularly indium-hafnium-zinc oxide (IHZO) has remarkable potential in applications such as high-resolution displays and 3D NAND. For the first time, we propose the fabrication of IHZO thin film transistors (TFTs) via thermal atomic layer deposition (TH-ALD). The preparation, electrical properties, and stability of IHZO TFTs are investigated. The performance of TFT deposited at 250 degrees C and annealed in N-2 atmosphere at 300 degrees C exhibits a high field-effect mobility (mu) of 22.53 cm(2)/Vs, a high I-on/I-off of similar to 10(7), a low threshold voltage (Vth) of 0.15 V, and a minimum subthreshold swing (SS) of 0.24 V/decade. Furthermore, the threshold voltage shifts (Delta Vth) in TFTs annealed in N-2 and O-2 are 0.31 and 0.16 V, respectively. These enhancements are attributed to the defects suppression and remaining ionized oxygen vacancies result in increased electron concentration in N-2-annealed films. In comparison, O-2 annealing causes a reduction in field effect mobility but concurrently enhances stability due to the direct passivation of defects, which leads to fewer oxygen vacancies. Additionally, Hf content can also impact the performance of TFT devices, even a small addition of Hf also results in the effective reduction of the carrier concentration. These findings provide valuable insights into the device mechanism of IHZO TFTs, presenting a novel avenue for comprehending and augmenting their overall performance.