Beneficial effect of hydrogen in aluminum oxide deposited through the atomic layer deposition method on the electrical properties of an indium–gallium–zinc oxide thin-film transistor

Abstract

Park (2016) Beneficial effect of hydrogen in aluminum oxide deposited through the atomic layer deposition method on the electrical properties of an indium-gallium-zinc oxide thin-film transistor, Journal gate dielectric exhibit poor transistor characteristics, such as low mobility, a high subthreshold slope, and huge hysteresis. Through DC and short-pulsed current-voltage (I-V) measurements, it was revealed that the degradation of the transistor performance stems from the charging and discharging phenomenon at the interface traps located in the interface between the a-IGZO semiconductor and the Al 2 O 3 gate insulator. It was found that the low-temperature Al 2 O 3 atomic layer deposition processed film contains a higher density of hydrogen atoms compared to high-deposition-temperature films. The study results show that a high concentration of hydrogen atoms can passivate the defect sites in the interface and bulk, which produces excellent transistor characteristics. This study demonstrated that hydrogen has a beneficial effect on the defect passivation for oxide TFTs. ARTICLE HISTORY

The Mobility Enhancement of Indium Gallium Zinc Oxide Transistors via Low-temperature Crystallization using a Tantalum Catalytic Layer

“…Amorphous metal oxide semiconductor thin-film transistors (TFTs) are used as the backplane electronics in liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays, for their field-effect mobility >10 cm 2 /V·s, good uniformity over large glass substrates sizes, and low temperature process 1 – 4 . Conventionally, amorphous silicon ( a -Si:H) has been the well-established standard backplane technology due to its low cost, good size scalability, and excellent manufacturability 5 .…”

Effect of the Gate Dielectric Layer of Flexible InGaZnO Synaptic Thin-Film Transistors on Learning Behavior

“…The connecting strength of our IGZO devices is determined by where hydrogens are located inside the gate insulator. It is known that the Al 2 O 3 layer deposited by low-temperature ALD contains significantly high hydrogen content, and these hydrogen atoms can be treated as electron donors by reacting with oxygen ions in IGZO. , This is because a high deposition temperature can enhance the desorption of residual species after the surface reaction, and the residual hydrogen ions can remain in the Al 2 O 3 film due to the incomplete removal of the hydroxyl groups. The migration of hydrogens toward and away from the IGZO channel by positive and negative gate pulses causes negative and positive V T changes, respectively.…”

“…The migration of hydrogens toward and away from the IGZO channel by positive and negative gate pulses causes negative and positive V T changes, respectively. It is believed that hydrogens rarely penetrate into the IGZO layer and the hydrogen content is much lower in the IGZO layer since hydrogen combines with O to form O–H when it reaches the IGZO interface. , The post-annealing process was not conducted in this work since hydrogens can passivate the interface traps between the active layer and the gate insulator and disappear by post-annealing …”

Combination of Gate-Stack Process and Cationic Composition Control for Boosting the Performance of Thin-Film Transistors Using In–Ga–Zn–O Active Channels Prepared by Atomic Layer Deposition

“…The profile intensities of H and OH species for the specimen treated with H 2 O-PL were examined to be doubled, compared with those of the specimen treated with O 3 -PL at interfaces between the PL and IGZO layers, which correspond to back-channel interface for the devices. Assuming that H’s typically act as shallow donors for the IGZO active layers, the differences in H content could have direct influences on the transfer characteristics of the TFTs. − The H’s formed by surface adsorption of H 2 O during the H 2 O ALD process can react with oxygens in the IGZO films to form OH bonds, and the free electrons can be generated, as described in the following reaction formula: H + O 2– → OH – + e – . As a result, the amounts of OH groups increase at the PL (H 2 O)/IGZO interface and work as strong electron donors, resulting in increases in conduction carrier concentration in the IGZO layer.…”