Temperature-Dependent Transfer Characteristics of Amorphous InGaZnO₄ Thin-Film Transistors

Abstract

The transfer characteristics of amorphous InGaZnO 4 thin-film transistors (a-IGZO TFTs) were measured at temperatures ranging from 298 to 523 K in order to analyze the behavior of the above-threshold (ON state) and subthreshold regions. For comparison, the transfer characteristics of a hydrogenated amorphous silicon TFT (a-Si:H TFT) were measured in the same temperature range. We developed a simple analytical model that relates the threshold voltage (V t ) decrease due to increasing temperature to the formation of point defects in a-IGZO. It is well known that the formation of point defects results in the generation of free carriers in oxide semiconductors. Incorporating the analytical model with the experimental transfer characteristics data taken at high temperatures over 423 K, we estimated the formation energy to be approximately 1.05 eV. The V t decrease because of the generation of point defects is peculiar to a-IGZO TFTs, which is not observed in a-Si:H TFTs. The results for the ON-current activation energy suggested that the density of tail states for a-IGZO is much lower than that for a-Si:H. #

Semiconductor to metallic transition in bulk accumulated amorphous indium-gallium-zinc-oxide dual gate thin-film transistor

“…Negative V TG shows an increment of saturation mobility with increasing temperature, due to the increment of free carrier concentrations by thermal excitation to the conduction band from localized states. 10,11,13 This trend is commonly observed in SG a-IGZO TFTs, while the Fermi level falls inside or below the tail states. 11 On the other hand, positive V TG shows an opposite trend on temperature dependent saturation mobility.…”

“…The temperature dependent characteristics of SG a-IGZO TFTs has been investigated by many groups to understand the conduction mechanism. [10][11][12] In this paper, we investigated the top gate voltage dependent transfer characteristics measured at bottom gate terminal and temperature (from 25 to 70 o C) dependency in DG a-IGZO TFTs. The temperature dependent transfer characteristics were measured for top gate biased (V TG ) -20, 15,-10, -5, 0, +5, +10, +15 and +20V sequentially.…”

Influence of Temperature on the Steady State and Transient Luminance of an OLED Display

“…Fig. 3 shows the luminance L M (T ) as a function of temperature T , relative to the luminance L M (20 • C) at 20…”

Microstructural Characteristics of InGaZnO Thin Film Using an Electrical Current Method

“…6) Notably, these papers reported that the chemical composition of the IGZO films is not stable, and there are still reliability problems in the interface zone of devices. 7) Both the composition and annealing temperature of IGZO thin films affect the film resistance and interface problems, 57) so stable IGZO thin film characteristics were obtained by using the co-sputtering system to deposit thin films and the samples were annealed with different depositing oxygen flow rates. 8,9) In fact, most single thin film systems have better electrical properties after an annealing treatment at 675 875 K for 12 h. For a double layer structure, high temperature annealing always decreases the reliability in the interface zone due to interface diffusion.…”

“…8,9) In fact, most single thin film systems have better electrical properties after an annealing treatment at 675 875 K for 12 h. For a double layer structure, high temperature annealing always decreases the reliability in the interface zone due to interface diffusion. 7,9,10) Electrical current testing is a low temperature process carried out in atmosphere. 11) Its mechanism is an electrical current induced crystallization (EIC) 12,13) that has been largely ignored in the optoelectronic thin films until now.…”