High-Performance Amorphous InGaZnO Thin-Film Transistor Gated by HfAlOₓ Dielectric With Ultralow Subthreshold Swing

All solution-processed hafnium rich hybrid dielectrics for hysteresis free metal-oxide thin-film transistors

“…34 In the case of HfAlO x –PVP hybrid films, this peak shifts to the low binding energy of 530.8 eV indicating the intermingling of both AlO x and HfO x for the formation of Hf–O–Al bonds 40 The minor shift to lower binding energy observed in this peak is due to the reduction of the Al content in HfAlO x –PVP hybrid films. The high intensity peak observed at 532.2 eV in the spectrum of the pristine AlO x –PVP film and at 531.9 eV for the case of the HfAlO x –PVP hybrid film corresponds to metal hydroxide bonds (M–OH, M = Al and Hf) 39 present in the hybrid dielectric films. The other high intensity peak in the O 1s spectra observed at 532.9 eV for both types of hybrid dielectric films can be assigned to M–O–C bonding (M = Al and Hf).…”

“…HfAlO x dielectric layers, deposited mainly by the atomic layer deposition method (ALD), have been widely utilized as gate dielectrics in the framework of various oxide TFTs. 39,40 Continuously, the mixture of Hf and Al in HfAlO x dielectric materials suppresses the oxygen vacancies and defects, 40 reducing the hysteresis to further enhance the electrical performance in TFTs. 41 However, high vacuum deposition methods are rather not compatible for large area deposition and low-cost fabrication applications in electronics.…”

Near-Ideal Top-Gate Controllability of InGaZnO Thin-Film Transistors by Suppressing Interface Defects with an Ultrathin Atomic Layer Deposited Gate Insulator

“…In order to enhance the gate controllability in short-channel AOS transistors, various high- k dielectrics deposited by atomic layer deposition (ALD) have been investigated to considerably reduce the equivalent oxide thickness (EOT) of the GI, such as HfO x , − LaAlO 3 , HfAlO x , and AlO x . − However, the conduction band offset (Δ E c ) between the AOS channel and high- k GI is lower than that between AOS and SiO 2 , which can arise the risk of charge injection to the conduction band of GI. , Among these dielectrics, AlO x has the largest Δ E c with a-IGZO, , which makes AlO x the most favorable high- k GI for AOS TFTs.…”

“…However, the self-aligned top-gate (SATG) AOS TFT with smaller parasitic capacitance and better scalability , is preferred by the advanced applications, wherein the post-AOS GI deposition places a daunting challenge on realizing ultrathin top-gate (TG) EOT with ALD high- k dielectrics. The associated ALD processes with chemically reactive species often induced abundant defect states at the GI/channel interface − and in the AOS channel. , These defect states can result in the increased off-state current ( I off ), a reduced on/off ratio, poor subthreshold swing (SS), and a negative threshold voltage ( V th ) shift, , while the defect-sensitive stabilities could deteriorate even more severely. , Therefore, it is highly desired to clarify the interaction mechanism between the top AlO x GI and the bottom a-IGZO channel, in order to direct the suppression of defect generation during the ALD process and thus enable the high performance and reliability of ultrathin-EOT SATG AOS TFTs.…”

59.9 mV·dec Subthreshold Swing Achieved in Zinc Tin Oxide TFTs With In Situ Atomic Layer Deposited AlO Gate Insulator

“…flexible electronics [1], [2], [3]. There have been many studies of different AOS materials, such as In 2 O 3 [4], InGaZnO (IGZO) [5], [6], [7], InZnO (IZO) [8], InGaSnO (IGTO) [9], and ZnSnO (ZTO) [2], [3], [10]. However, IGZO, IZO, and IGTO all contain indium, which is comparatively rare [11].…”