Improved performance and stability of In-Sn-Zn-O thin film transistor by introducing a meso-crystalline ZrO2 high-k gate insulator

Abstract

Electrical characteristics and reliability of an In-Sn-Zn-O (ITZO) thin film transistor (TFT) using ZrO2 as a high-k gate insulator were investigated. Varying the atomic layer deposition process temperature caused differences in the ZrO2 thin film chemical state and microstructure. Corresponding changes in the electrical properties of the thin film were evaluated. While the ZrO2 thin film deposited at 300 °C exhibited an excellent thin film property, the best TFT performance as measured by subthreshold swing, effective mobility, and on/off ratio was achieved with deposition at 250 °C. The formation of meso-crystalline structure and subsequent low leakage current density enhanced the TFT performance along with the suppression of Coulombic scattering and interface defect formation. Moreover, the reliability of the TFT was demonstrated using both positive and negative bias temperature stress measurements.

Characteristics of High‐Crystallinity ZrO2Thin Films Deposited Using Remote Plasma Atomic Layer Deposition

“…These represent the contributions of metal—oxygen bonds without oxygen vacancies, in oxygen‐deficient regions, and in hydroxide bonds, respectively. [ 22 ] The OH peaks’ contribution to the O1s spectrum is 6.2%, 6.9%, and 10.8% at plasma powers 50, 100, and 1000 W, respectively. OH bonding is observed in both the Zr3d and O1s spectra, and the ratio of OH‐related peaks increases as plasma power increases.…”

Recent advances in the understanding of high-kdielectric materials deposited by atomic layer deposition for dynamic random-access memory capacitor applications

“…However, when Al 2 O 3 was used as a dopant, it inhibited coalescence of the dielectric, resulting in a smaller grain crystal structure of the matrix dielectric. In this regard, a "mesocrystalline" structure was suggested for reducing leakage current [25,46]. The mesocrystalline structure consisted of partially crystallized grains incorporated in an amorphous matrix.…”

Thermopower Modulation Analyses of High-Mobility Transparent Amorphous Oxide Semiconductor Thin-Film Transistors

“…Numerous studies have reported that ITZO-TFTs possess high μ FE values. − In 2021, Shiah et al found an ITZO-TFT with an extremely high μ FE of 70 cm 2 V –1 s –1 , demonstrating the potential of these TFTs. However, the origin of their high μ FE has yet to be clarified.…”